Hillary Clinton Didn't Think Pneumonia Diagnosis Would Be 'That Big a Deal'

PHOTO: Democratic presidential candidate Hillary Clinton speaks to members of the media before boarding her campaign plane at Westchester County Airport in White Plains, New York, Sept. 8, 2016.PlayAndrew Harnik/AP Photo
WATCH Hillary Clinton Gives Update on Her Health

Hillary Clinton said she didn't disclose that she had pneumonia last week because she "didn't think it was going to be that big a deal," she said in an interview Monday night.

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The issue of Clinton's health has dogged her on the campaign trail, and it came into focus when she left a 9/11 ceremony early and lost her balance outside her van in New York City on Sunday.

Clinton previously attributed a cough she had to allergies, but she was diagnosed Friday with pneumonia, her doctor said.

She was placed on antibiotics.

"I'm feeling so much better, and obviously I should have gotten some rest sooner," she told CNN's Anderson Cooper by phone Monday.

"I just thought I could keep going forward and power through it, and obviously that didn't work out so well."

Clinton said that after she got into the air-conditioned van and got some water, she felt better. But she denied that she passed out.

"No, I didn't. I felt dizzy, and I did lose my balance for a minute, but once I got in, once I could sit down, once I could cool off, once I had some water, I immediately started feeling better," she told CNN.

She said she thought it was allergies, but when her cough didn't go away, she was checked by her doctor.

"Obviously, I was supposed to rest five days," she said. "That's what they told me on Friday, and I didn't follow that very wise advice. So I just want to get this over and done with and get back on the trail as soon as possible."