Nationwide raids on undocumented immigrants are expected to start Sunday, a crackdown that President Trump originally said would remove “millions” of people in the U.S. illegally but now will focus on 2,000 people who have already been ordered deported.

The raids may happen or they may be canceled again at the last minute, as they were last month. Either way, the prospect is sowing fear, confusion and panic in many families like Diana Hidalgo’s.

Diana is only 17, but she’s lived long enough to know what even the prospect of such raids will lead to for family, friends and neighbors in Antioch: “chaos.”

“It’s giving everyone the feeling of, ‘What’s going to happen?’” she said. “They have that up-front face that says, ‘Be tough.’ But people are worrying all the time.”

Next week ICE will begin the process of removing the millions of illegal aliens who have illicitly found their way into the United States. They will be removed as fast as they come in. Mexico, using their strong immigration laws, is doing a very good job of stopping people....... — Donald J. Trump (@realDonaldTrump) June 18, 2019

Diana is a native-born U.S. citizen. Her mother, who was born in Mexico, has her green card. Neither of them has any reason to fear a raid, but they do. They worry about other family members and friends who are not here legally. They share information from social media about what to do if Immigration and Customs Enforcement agents come to their door.

Some of her young friends who are U.S. citizens have contingency plans should their undocumented-immigrant parents be arrested by ICE agents.

Rubiel Cadena is among them. At 17, he is the youngest of three children and the only one born in this country. His mother, father and two brothers lack legal status to be in the U.S. His parents have told him that if anything happens to them, he will have to live with family friends nearby.

“They’re here locally, so I don’t have to change anything school-wise,” said Rubiel , who is planning to attend Los Medanos College in nearby Pittsburg this fall. “They’re really caring. It’s a safe haven. They are foster parents, so they’re experienced with taking in kids.”

The family’s previous plan was for Rubiel to live with his godfather in Nevada. But he was undocumented, and he’s been deported.

“And that’s the thing I always worry about,” Cadena said. “My parents and my brothers — that’s everyone we have. We don’t have family in California. The closest family we have is all the way in Texas. It’s really scary that I could be all on my own here.”

Diana has known that fear since she was a young girl. She would be sitting in the kitchen, doing her homework while her parents were in the living room, listening to the news.

“And I would hear something (on the news) and wonder, ‘What’s going to happen? Am I going to be left alone?’” Diana said.

“And then my mom would say to me, ‘Don’t worry. If something happens to me, you would stay with your dad or your uncle. You’re going to be OK.’”

The fear was still with her even after Diana’s mother got her green card. The two recently traveled to Mexico and flew home to the U.S. As they approached the security checkpoint at the airport, Diana froze.

“I thought, ‘My mom!’ But then I took a breath in and remembered, ‘OK, she has her residency,’” she said. “It wasn’t a worry anymore, but it was still was like, ‘Could they take it away?’”

Her brother, Jose Hidalgo-Angeles, 15, worries about their cousins, uncles and friends. “Most are here legally, but they’re still scared,” he said.

“They’re scared that they might be sent back and they won’t be able to do anything anymore,” Jose said. “The main reason they came here is to get a better life, especially for their kids, and to send money back” from their construction jobs to relatives in Mexico.

Jose looks up to one uncle “who knows a lot about this because he watches the news and he likes to be informed. I admire him for that.”

“I’m still worried, because he doesn’t have his papers and he’s not legal,” he said.

Others wonder whether they should believe what swirls around social media. Some rumors are baseless, but they are what these teenagers see: ICE will target legal permanent residents, or will revoke the citizenship of immigrants who recently earned it.

Other reports are not baseless. The government has said there are likely to be “collateral deportations” of undocumented immigrants who aren’t targeted by the ICE raids, but who happen to be near those who are when agents come calling.

“I heard that they could take citizenship away from me, even though I was born here,” said Jose Cordon, 26, who works with young people at One Day at a Time, an organization in Brentwood that serves a largely Latino constituency in eastern Contra Costa County. “When I heard that, it was a little bit more concerning.

“I’m American, you feel me,” Cordon said. “Just how far could it potentially go?”

He hears the fears expressed by the young people he works with, and harbors similar ones about his family. Cordon’s mother is a U.S. citizen, but he’s still worried about what could happen to her and the people at the barbershop she owns in Antioch.

“A place like that — it could be a target,” Cordon said. “They know it’s a Latin place. More than likely if it’s a Spanish business, you’re going to have immigrants there.

“My mom, I don’t know how worried she is, but the atmosphere within that barbershop? People are worried,” Cordon said. He said his mother would feel helpless if she saw customers “being escorted out the door” and was powerless to stop it.

Part of that helplessness and suspicion of government stems from where Cordon’s parents grew up. His mother emigrated from El Salvador during its civil war of the 1980s, where government-backed death squads killed thousands of civilians. His father grew up in Guatemala, where the government supported similar atrocities.

Cordon surveys the current U.S. political climate: “It’s a very powerless time.”

Joe Garofoli is The San Francisco Chronicle’s senior political writer. Email: jgarofoli@sfchronicle.com Twitter: @joegarofoli