Greensboro, North Carolina (CNN) Hillary Clinton returned to the campaign trail Thursday, four days after her near fainting spell, with little room for another misstep.

The moment she took the stage, Clinton addressed the topic that has overwhelmed headlines since Sunday: Her health. She acknowledged to the Greensboro, North Carolina, crowd that being forced to stay at home following her pneumonia diagnosis at such a crucial moment in the election wasn't easy to stomach.

"As you may know, I recently had a cough that turned out to be pneumonia. I tried to power through it but even I had to admit that maybe a few days of rest would do me good," Clinton said, after walking out into a school gymnasium to James Brown's "I Got You (I Feel Good)." "I'm not great at taking it easy even under ordinary circumstances, but with just two months to go until Election Day, sitting at home was pretty much the last place I wanted to be."

After grudgingly following her doctor's orders to slow down and rest to recuperate from pneumonia -- and watching Donald Trump seize the spotlight and pull even or ahead in some key swing states such as Ohio -- the Democratic presidential nominee has signaled she is eager to make a feisty comeback at a crucial moment in the election.

One of the last times the public saw Clinton, she was being helped into a van by her security detail, her knees buckling and body slouching over as she lost her balance.

Clinton said she spent the time at home reflecting, as she mused that "the campaign trail doesn't really encourage reflection."

"It turns out, having a few days to myself was actually a gift," she said.

With less than two months until Election Day, polls have begun to tighten. In Clinton's absence, Trump and his surrogates were free to relentlessly attack the former secretary of state with relatively little pushback. Trump particularly zeroed in on Clinton's in artful comments from last Friday night, in which she described half of Trump's supporters as being in a "basket of deplorables."

Photos: Hillary Clinton's life in the spotlight Hillary Clinton accepts the Democratic Party's nomination for president at the Democratic National Convention in Philadelphia on July 28, 2016. The former first lady, U.S. senator and secretary of state was the first woman to lead the presidential ticket of a major political party. Hide Caption 1 of 43 Photos: Hillary Clinton's life in the spotlight Before marrying Bill Clinton, she was Hillary Rodham. Here she attends Wellesley College in Massachusetts. Her commencement speech at Wellesley's graduation ceremony in 1969 attracted national attention. After graduating, she attended Yale Law School. Hide Caption 2 of 43 Photos: Hillary Clinton's life in the spotlight Rodham was a lawyer on the House Judiciary Committee, whose work led to impeachment charges against President Richard Nixon in 1974. Hide Caption 3 of 43 Photos: Hillary Clinton's life in the spotlight In 1975, Rodham married Bill Clinton, whom she met at Yale Law School. He became the governor of Arkansas in 1978. In 1980, the couple had a daughter, Chelsea. Hide Caption 4 of 43 Photos: Hillary Clinton's life in the spotlight Arkansas' first lady, now using the name Hillary Rodham Clinton, wears her inaugural ball gown in 1985. Hide Caption 5 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons celebrate Bill's inauguration in Little Rock, Arkansas, in 1991. He was governor from 1983 to 1992, when he was elected President. Hide Caption 6 of 43 Photos: Hillary Clinton's life in the spotlight Bill Clinton comforts his wife on the set of "60 Minutes" after a stage light broke loose from the ceiling and knocked her down in January 1992. Hide Caption 7 of 43 Photos: Hillary Clinton's life in the spotlight In June 1992, Clinton uses a sewing machine designed to eliminate back and wrist strain. She had just given a speech at a convention of the International Ladies' Garment Workers Union. Hide Caption 8 of 43 Photos: Hillary Clinton's life in the spotlight During the 1992 presidential campaign, Clinton jokes with her husband's running mate, Al Gore, and Gore's wife, Tipper, aboard a campaign bus. Hide Caption 9 of 43 Photos: Hillary Clinton's life in the spotlight Clinton accompanies her husband as he takes the oath of office in January 1993. Hide Caption 10 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons share a laugh on Capitol Hill in 1993. Hide Caption 11 of 43 Photos: Hillary Clinton's life in the spotlight Clinton unveils the renovated Blue Room of the White House in 1995. Hide Caption 12 of 43 Photos: Hillary Clinton's life in the spotlight Clinton waves to the media in January 1996 as she arrives for an appearance before a grand jury in Washington. The first lady was subpoenaed to testify as a witness in the investigation of the Whitewater land deal in Arkansas. The Clintons' business investment was investigated, but ultimately they were cleared of any wrongdoing. Hide Caption 13 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons hug as Bill is sworn in for a second term as President. Hide Caption 14 of 43 Photos: Hillary Clinton's life in the spotlight The first lady holds up a Grammy Award, which she won for her audiobook "It Takes a Village" in 1997. Hide Caption 15 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons dance on a beach in the U.S. Virgin Islands in January 1998. Later that month, Bill Clinton was accused of having a sexual relationship with former White House intern Monica Lewinsky. Hide Caption 16 of 43 Photos: Hillary Clinton's life in the spotlight Clinton looks on as her husband discusses the Monica Lewinsky scandal in the Roosevelt Room of the White House on January 26, 1998. Clinton declared, "I did not have sexual relations with that woman." In August of that year, Clinton testified before a grand jury and admitted to having "inappropriate intimate contact" with Lewinsky, but he said it did not constitute sexual relations because they had not had intercourse. He was impeached in December on charges of perjury and obstruction of justice. Hide Caption 17 of 43 Photos: Hillary Clinton's life in the spotlight The first family walks with their dog, Buddy, as they leave the White House for a vacation in August 1998. Hide Caption 18 of 43 Photos: Hillary Clinton's life in the spotlight President Clinton makes a statement at the White House in December 1998, thanking members of Congress who voted against his impeachment. The Senate trial ended with an acquittal in February 1999. Hide Caption 19 of 43 Photos: Hillary Clinton's life in the spotlight Clinton announces in February 2000 that she will seek the U.S. Senate seat in New York. She was elected later that year. Hide Caption 20 of 43 Photos: Hillary Clinton's life in the spotlight Clinton makes her first appearance on the Senate Environment and Natural Resources Committee. Hide Caption 21 of 43 Photos: Hillary Clinton's life in the spotlight Sen. Clinton comforts Maren Sarkarat, a woman who lost her husband in the September 11 terrorist attacks, during a ground-zero memorial in October 2001. Hide Caption 22 of 43 Photos: Hillary Clinton's life in the spotlight Clinton holds up her book "Living History" before a signing in Auburn Hills, Michigan, in 2003. Hide Caption 23 of 43 Photos: Hillary Clinton's life in the spotlight Clinton and another presidential hopeful, U.S. Sen. Barack Obama, applaud at the start of a Democratic debate in 2007. Hide Caption 24 of 43 Photos: Hillary Clinton's life in the spotlight Obama and Clinton talk on the plane on their way to a rally in Unity, New Hampshire, in June 2008. She had recently ended her presidential campaign and endorsed Obama. Hide Caption 25 of 43 Photos: Hillary Clinton's life in the spotlight Obama is flanked by Clinton and Vice President-elect Joe Biden at a news conference in Chicago in December 2008. He had designated Clinton to be his secretary of state. Hide Caption 26 of 43 Photos: Hillary Clinton's life in the spotlight Clinton, as secretary of state, greets Russian Prime Minister Vladimir Putin during a meeting just outside Moscow in March 2010. Hide Caption 27 of 43 Photos: Hillary Clinton's life in the spotlight The Clintons pose on the day of Chelsea's wedding to Marc Mezvinsky in July 2010. Hide Caption 28 of 43 Photos: Hillary Clinton's life in the spotlight In this photo provided by the White House, Obama, Clinton, Biden and other members of the national security team receive an update on the mission against Osama bin Laden in May 2011. Hide Caption 29 of 43 Photos: Hillary Clinton's life in the spotlight Clinton checks her Blackberry inside a military plane after leaving Malta in October 2011. In 2015, The New York Times reported that Clinton exclusively used a personal email account during her time as secretary of state. The account, fed through its own server, raises security and preservation concerns. Clinton later said she used a private domain out of "convenience," but admits in retrospect "it would have been better" to use multiple emails. Hide Caption 30 of 43 Photos: Hillary Clinton's life in the spotlight Clinton arrives for a group photo before a forum with the Gulf Cooperation Council in March 2012. The forum was held in Riyadh, Saudi Arabia. Hide Caption 31 of 43 Photos: Hillary Clinton's life in the spotlight Obama and Clinton bow during the transfer-of-remains ceremony marking the return of four Americans, including U.S. Ambassador Christopher Stevens, who were killed in Benghazi, Libya, in September 2012. Hide Caption 32 of 43 Photos: Hillary Clinton's life in the spotlight Clinton ducks after a woman threw a shoe at her while she was delivering remarks at a recycling trade conference in Las Vegas in 2014. Hide Caption 33 of 43 Photos: Hillary Clinton's life in the spotlight Clinton, now running for President again, performs with Jimmy Fallon during a "Tonight Show" skit in September 2015. Hide Caption 34 of 43 Photos: Hillary Clinton's life in the spotlight Clinton testifies about the Benghazi attack during a House committee meeting in October 2015. "I would imagine I have thought more about what happened than all of you put together," she said during the 11-hour hearing. "I have lost more sleep than all of you put together. I have been wracking my brain about what more could have been done or should have been done." Months earlier, Clinton had acknowledged a "systemic breakdown" as cited by an Accountability Review Board, and she said that her department was taking additional steps to increase security at U.S. diplomatic facilities. Hide Caption 35 of 43 Photos: Hillary Clinton's life in the spotlight U.S. Sen. Bernie Sanders shares a lighthearted moment with Clinton during a Democratic presidential debate in October 2015. It came after Sanders gave his take on the Clinton email scandal. "The American people are sick and tired of hearing about the damn emails," Sanders said. "Enough of the emails. Let's talk about the real issues facing the United States of America." Hide Caption 36 of 43 Photos: Hillary Clinton's life in the spotlight Clinton is reflected in a teleprompter during a campaign rally in Alexandria, Virginia, in October 2015. Hide Caption 37 of 43 Photos: Hillary Clinton's life in the spotlight Clinton walks on her stage with her family after winning the New York primary in April. Hide Caption 38 of 43 Photos: Hillary Clinton's life in the spotlight After Clinton became the Democratic Party's presumptive nominee, this photo was posted to her official Twitter account. "To every little girl who dreams big: Yes, you can be anything you want -- even president," Clinton said. "Tonight is for you." Hide Caption 39 of 43 Photos: Hillary Clinton's life in the spotlight Obama hugs Clinton after he gave a speech at the Democratic National Convention in Philadelphia. The president said Clinton was ready to be commander in chief. "For four years, I had a front-row seat to her intelligence, her judgment and her discipline," he said, referring to her stint as his secretary of state. Hide Caption 40 of 43 Photos: Hillary Clinton's life in the spotlight Clinton arrives at a 9/11 commemoration ceremony in New York on September 11. Clinton, who was diagnosed with pneumonia two days before, left early after feeling ill. A video appeared to show her stumble as Secret Service agents helped her into a van. Hide Caption 41 of 43 Photos: Hillary Clinton's life in the spotlight Clinton addresses a campaign rally in Cleveland on November 6, two days before Election Day. She went on to lose Ohio -- and the election -- to her Republican opponent, Donald Trump. Hide Caption 42 of 43 Photos: Hillary Clinton's life in the spotlight After conceding the presidency to Trump in a phone call earlier, Clinton addresses supporters and campaign workers in New York on Wednesday, November 9. Her defeat marked a stunning end to a campaign that appeared poised to make her the first woman elected US president. Hide Caption 43 of 43

In a more reflective speech than normal, Clinton admitted some of her shortcomings, including having "a tendency to over prepare" like "a lot of women."

"I sweat the details whether we are talking about the exact number of lead in the water in Flint or how many North Carolina kids are in early enrichment programs or the precise interest rate on your student loans, right down to the decimal."

And even though the Clinton campaign disclosed more information about her health on Wednesday, its initial decision to not immediately reveal the candidate's pneumonia diagnosis until late Sunday -- well after she left the September 11 memorial and briefly disappeared from reporters assigned to follow her -- has raised a slew of fresh criticism about the lack of transparency.

Clinton returned to the campaign trail with a rally in Greensboro and will follow up with a speech at a Congressional Hispanic Caucus gathering in Washington in the evening.

In Greensboro, Clinton spoke about the issue of "how we lift up our children and families," in remarks that marked Clinton's second in a series of "Stronger Together" speeches -- part of a broader effort to inject more of the candidate's personal story into the narrative.

"One upside to Hillary Clinton's break from the trail was having time to sharpen the final argument she will present to voters in these closing weeks," communications director Jennifer Palmieri said in a statement ahead of the speech.

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But if Clinton is trying to change the subject away from her health, Trump may make that difficult. After largely staying away from commenting on Clinton's recent health episode, he took a swipe at his opponent's stamina at a rally in Canton, Ohio, Wednesday night.

"I don't know folks -- do you think Hillary Clinton would be able to stand up here for an hour? I don't know," Trump mused.

Clinton was originally scheduled to travel to the West Coast on Monday, where she planned to deliver a message aimed at millennial voters in California and Nevada. And her remarks in Los Angeles on Tuesday were meant to about a more inclusive economy.

All of those plans fell through when Clinton stumbled at the 9/11 memorial ceremony on Sunday, and it's not clear when the campaign will reschedule those events.

When Kaine knew about pneumonia diagnosis

Clinton declined to address when her running mate Tim Kaine knew about her pneumonia diagnosis, as she faced questions about the nature of her partnership with her running mate on her first day back on the campaign trail.

In a news conference following her remarks, Clinton was directly asked when she informed Kaine that she had pneumonia. Her doctor made the diagnosis Friday, but the public did not find out about it until Sunday.

"My senior staff knew and information was provided to a number of people. And look -- this was an ailment that many people just power through and that's what I thought I would do as well," Clinton said, not addressing the specific Kaine question. "I didn't want to stop, I didn't want to quit campaigning, I certainly didn't want to miss the 9/11 memorial."

Democratic vice presidential nominee U.S. Sen Tim Kaine (D-VA) looks on during a campaign rally with democratic presidential nominee former Secretary of State Hillary Clinton at the David L. Lawrence Convention Center on July 30, 2016 in Pittsburgh, Pennsylvania.

Another reporter followed up, asking how often Clinton speaks with Kaine and how she views her relationship and working partnership with her running mate.

Clinton said she communicated with Kaine as late as Wednesday night and referred to him as a "great partner" and great future vice president.

"We've communicated but I'm not going to go into our personal conversations and I feel very comfortable and confident about our relationship," Clinton added.

Kaine has also been asked about his knowledge of Clinton's diagnosis, and suggested in Dayton on Monday that he was in the dark until Sunday.

"I don't want to talk about her and my conversations, the content of them, except just to say that I reached out to her as soon as the incident happened on Sunday, as soon as I was aware of it," Kaine said.

When pressed to clarify if he didn't know about Clinton's diagnosis on Friday, Kaine responded: "I can just say, I'm not going to get into the content, but we talked yesterday after the incident happened."

North Carolina's importance

Clinton is sending a message by choosing North Carolina — a state her campaign believes is a must-win for Trump -- as her first stop back on the trail. Trump has a 5 point lead in Ohio and a 3 point cushion in Florida, according to a new CNN-ORC poll released Wednesday, meaning the Tar Heel State is increasingly important for Clinton as well.

Then-Sen. Barack Obama won North Carolina in 2008, while Republican nominee Mitt Romney won in 2012. Clinton's top aides believe North Carolina may be more solidly blue than typical bellwethers like Ohio because of the abundance of African-American and college-educated white voters.

North Carolina has a larger than average number of college-educated whites, buoyed by growth of college and post-college white voters in the Durham, Raleigh and Chapel Hill area.

Democratic pollster Geoff Garin said North Carolina is Clinton's "best chance" to win a state that Mitt Romney carried four years ago.

"Polls consistently have showed her holding a narrow plurality in the state, built on strong support among African-Americans and an ability to win over some better educated suburban whites in the Charlotte area and the Research Triangle who liked Romney but find Trump out of sync with their values," said Garin, who advises the pro-Clinton super PAC Priorities USA.

Thursday's visit is her fifth since she clinched the nomination on June, while Clinton's campaign and her aligned super PACs have spent close to $15 million advertising on TV in the state. And by the time she visits on Thursday, Clinton's Tar Heel State operation will have 33 organizing offices in the state.

Clinton has so far struggled break away from Trump in states like Nevada, New Hampshire and Ohio, which have smaller than average numbers of college educated white voters. While Trump has led with white voters, those with college degrees have rejected Trump in larger numbers than past elections.

While Obama lost college-educated white voters by 14 points, national polls in August found Clinton up by 10 points with the group.

But as polls tighten, so has Clinton's advantage with that group. CNN/ORC polls released Wednesday found that Trump actually leads by 9 points among the group in Ohio and 8 points in Florida.

Clinton knows she needs to be on the trail in order to seize back momentum she had earlier this summer. And she says it's been difficult to follow her doctor's orders.

"I was supposed to rest five days -- that's what they told me on Friday -- and I didn't follow that very wise advice," Clinton told CNN's Anderson Cooper Monday night. "So I just want to get this over and done with and get back on the trail as soon as possible."