LISBON, Maine — Hillary Clinton’s already horrific week — from double-digit Obamacare premium hikes to damaging internal memos detailing “Bill Clinton Inc.,” to shrinking leads in the polls — ended with yet another humiliating controversy as the FBI said it’s probing new campaign emails.

In an abrupt October shocker, FBI Director James B. Comey told Congress in a letter that the agency is investigating whether classified information exists in emails discovered in the sexting investigation of former Brooklyn U.S. Rep. Anthony Weiner, whose estranged wife, Huma Abedin, is Clinton’s close aide.

“Hillary Clinton’s corruption is on a scale that we’ve never seen before,” Donald Trump said yesterday to a roaring crowd at a rally in Manchester, N.H., minutes after the news broke. “We cannot let her take her criminal scheme into the Oval Office.”

Clinton was already enduring a week from political hell, beginning with news that Obamacare premiums would increase for some plans by an average of 25 percent. Clinton has touted Obamacare on the trail, even going so far as to suggest to people that it used to be called “Hillarycare.”

Then a new 2011 memo — released by WikiLeaks — detailed the lengths Bill Clinton aide Doug Band went to in leveraging his corporate clients for at least $50 million in speaking fees, honoraria and other pricey perks for the former president, while also raising funds for the Clinton Foundation.

Even before news of the emails yesterday, Clinton’s lead was slipping in national polls. An ABC News Tracking Poll showed the former secretary of state’s 12-point lead on Tuesday slide to 4 points.

All of this came as voters were already casting their ballots across the country with less than two weeks before Election Day.

The fact that Clinton’s email scandal, which aides felt they had finally put behind them, would resurface at the 11th hour was a major stunner even in an election season known for unusual twists.

“This helps Trump in a time when he needs help,” Republican strategist Ford O’Connell said. “It will help him close the gap, but we’ll know better by Monday or Tuesday just how much this will help him. … The Clinton camp is running for cover. … This is a boost for Trump at the right time.”

Trump joked in New Hampshire that perhaps the system wasn’t so rigged after all.

“This was a grave miscarriage of justice that the American people fully understood,” Trump said of the Clinton email scandal. “And it’s everybody’s hope it is about to be corrected.

“With that said,” Trump told the crowd, “the rest of my speech is going to be so boring. Should I even make the speech?”

Trump only briefly mentioned the developments at a second rally here at a church just outside Lewiston last night.

It’s a sign the Trump campaign is carefully trying to avoid overplaying its hand and risking the notoriously unscripted billionaire saying something that would take the spotlight off Clinton.