(AP) -- When Hillary Clinton was diagnosed with pneumonia late last week, she informed a handful of her closest advisers, but pressed on with a busy campaign schedule and did not inform the public that she was sick. "I just didn't think it was going to be that big a deal," she said.

Clinton's first comments about her health condition came in a CNN interview late Monday, a day after a dizzy spell caught on video forced the Democratic nominee to disclose her illness and cancel a West Coast campaign trip.

The incident reinforced Clinton's reputation as a public figure with a predisposition for privacy. While her top campaign aides conceded they were too slow in providing the public with information about Clinton's condition, it was unclear how quickly they themselves had been informed by the candidate.

In a move aimed at quieting questions about transparency, Clinton said she would be releasing more medical information this week. Her campaign has sought to turn the matter around on Republican opponent Donald Trump, who has released only a glowing letter from his doctor, though the billionaire real estate mogul says that he, too, plans to make public additional information in the coming days.

Less than two months from Election Day, Clinton's handling of her health incident added to Democrats' growing sense of uncertainty about the presidential race. While Democrats said the matter is unlikely to fundamentally alter the presidential race, Democrats worry the race with Trump is too close for comfort.

"If you look at the way the last couple months have gone, it feels like the race should be further apart," said Greg Haas, an Ohio-based Democratic strategist and former county party chairman.

Aaron Regunberg, a Democratic state representative from Rhode Island, said he was "surprised and concerned" that the race is so tight.

"I still think that we are likely to win, but I think anyone who's not concerned about a bigoted, KKK-endorsed sociopath being this close right now in the polls is not living in reality," Regunberg said of Trump.

Clinton abruptly left a 9/11 anniversary event Sunday in New York and was seen on video stumbling and being held up by aides. After roughly 90 minutes of silence from her campaign, aides said Clinton left because she was overheated. Several hours later, her doctor acknowledged she had been diagnosed with pneumonia two days earlier.

Clinton spent Monday at her home in Chappaqua, New York, after canceling a fundraising trip in California. It was unclear when she planned to return to the campaign trail.

In a text message to supporters Monday night, Clinton wrote: "Like anyone who's ever been home sick from work, I'm just anxious to get back out there."

Trump showed surprising restraint regarding Clinton's health. He wished her well and did not repeat questions he has previously raised about whether the former secretary of state has the strength and stamina to be president.

He did hammer Clinton for her assertion Friday night that half of his supporters belong in a "basket of deplorables" and are racist, sexist, homophobic or xenophobic. Clinton later said she regretted applying that description to "half" of Trump's backers, but stuck by her assertion that the GOP nominee has given a platform to "hateful views and voices."

Speaking in Maryland Monday, Trump said he was shocked to hear Clinton "attack, slander, smear and demean these wonderful, amazing people who are supporting our campaign."

After a staff shake-up in August, Trump has largely abandoned the free-wheeling style of campaigning that energized his supporters but also led to an endless string of controversial comments about women, minorities and others. The Republican nominee's newfound ability to stay on script has coincided with tightening in both national polls and surveys in some key swing states.

"The last few days feed into a sense of uncertainty," said Chris Kofinis, a Democratic strategist. He said Clinton's rough weekend raises the stakes for the first presidential debate on Sept. 26, which "will either finish Trump or, if he does well, it will create a race."

Privately, some Republicans say Trump would likely be losing more convincingly to another Democratic nominee. But Clinton's unpopularity rivals that of her opponent, and she's been unable to do much to change the minds of Americans who believe she is dishonest and secretive.

To be sure, Clinton continues to have numerous advantages over Trump as the race presses into its final weeks.

Polls show Trump struggling mightily with big swaths of the electorate, including women, blacks, Hispanics and young people. His path to the 270 Electoral College votes needed to win in November is also narrow -- he likely needs to carry Ohio, Florida, Pennsylvania and North Carolina -- while Clinton has numerous routes. Clinton's campaign is also running a sophisticated voter targeting and turnout operation, led by several people involved in President Barack Obama's winning campaigns, while Trump is banking on the Republican National Committee for his field operations.

Given those built-in advantages and Trump's weaknesses, some Democrats say their biggest fear is complacency -- making the tightening of the race not such a bad development.

"It really says to me and other supporters of Hillary that we have to be invested, and we're going to have to get out and work," said Missouri state Rep. Margo McNeil of suburban St. Louis, who was a Clinton delegate to the Democratic National Convention.

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AP writers Meg Kinnard in Columbia, South Carolina, Michelle R. Smith in Providence, Rhode Island, David Lieb in Jefferson City, Missouri, Lisa Lerer in White Plains, New York, and Ken Thomas in Washington contributed to this report.

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