Hillary Clinton says she is "feeling fine and getting better," as she recovers from pneumonia at her home in Chappaqua, outside New York City.
"Like anyone who's ever been home sick from work, I'm anxious to get back out there. See you on the (campaign) trail soon," Clinton tweeted.
Clinton's doctor diagnosed her with pneumonia on Friday.
She told cnn Monday that she ignored her doctor's advice to take it easy because she said she was "incredibly committed" to being at a September 11 anniversary event in New York City Sunday.
Clinton said she thought she could "power through" the event, but got overheated and had to leave early.
Video showed her nearly collapsing while being helped into her car. Her knees appeared to buckle under her.
Aides drove her to her daughter Chelsea's New York apartment, where she emerged several hours later, looking bright and telling reporters she felt great.
Clinton officials canceled campaign appearances Monday and Tuesday in California. She is under a doctor's orders to modify her schedule and get some rest.
Clinton Monday thanked everyone who sent their best wishes, which included Republican rival Donald Trump.
"I hope she gets well and gets back on the trail and we'll be seeing her in the debate," Trump said Monday, looking forward to their first face-to-face meeting September 26.