Hillary Clinton has said in a telephone interview that she is feeling “so much better”, a day after being taken ill at a 9/11 commemoration.
She also told CNN that she had not disclosed a recent pneumonia diagnosis because “I just didn’t think it was going to be that big a deal”.
The US presidential candidate said she had ignored a doctor’s “wise” advice to rest for five days.
Her rival Donald Trump said health had now become “an issue” in the campaign.
Mrs Clinton said during the phone interview that she hoped to be back on the trail in “the next couple of days”.
The Democratic nominee acknowledged she had lost her balance during Sunday morning’s health scare, but said she did not faint.
“I felt dizzy and I did lose my balance for a minute, but once I got in (the van), once I could sit down, once I could cool off, once I had some water, I immediately started feeling better,” she said.
Doctors later said she had been diagnosed with pneumonia on Friday.
Some critics questioned why this had only been revealed after Sunday’s events and Mrs Clinton’s communications director conceded the incident had been poorly managed.
She will be releasing new medical records to help ease concerns about her health, a campaign spokesman said.
It capped a difficult weekend for Mrs Clinton, who came under attack from Mr Trump for calling half of his supporters “deplorable” people on Friday.
On Monday, the Republican presidential nominee wished her a speedy recovery.
He also pledged to release the results of a medical examination he took over the past week.
Mr Trump has repeatedly suggested Mrs Clinton is unfit, telling supporters last month she “lacks the mental and physical stamina” to serve as president.
The Clinton campaign has accused opponents of pushing a “deranged conspiracy” about her health.
Major fall or just a stumble? – Anthony Zurcher, BBC News
Will Hillary Clinton’s near collapse during Sunday’s 9/11 memorial ceremonies make her health a political Achilles heel?
The Trump campaign managed to hold its tongue as the news unfolded, probably sensing that the story was damaging enough on its own.
At 68, Mrs Clinton is particularly susceptible to concerns about her health (as is 70-year-old Mr Trump).
But if she returns to her normal campaign schedule without incident, she will go a long way towards putting health concerns to bed.