After his agonising US Open loss last month, McIlroy had said he would take a few weeks away from the game to "process everything".
He was in position to end his hunt for a fifth major but threw it away with three bogeys in his final four holes, including two where he missed putts inside four feet, and lost to American Bryson DeChambeau by one stroke.
"I would say maybe like three or four days after (that it took to get over the pain of losing)," McIlroy told reporters.
"Went from being very disappointed and dejected to trying to focus on the positives to then wanting to learn from the negatives and then getting to the point where you become enthusiastic and motivated to go again.
"So it probably took three, four, five days. It's funny how your mindset can go from I don't want to see a golf course for a month to like four days later being can't wait to get another shot at it.
"When that disappointment turns to motivation, that's when it's time to go again."
Having won The Open in 2014, McIlroy said the talks around his next major win do not bother him.
The world number two owns 40 worldwide professional victories, 26 of which have come on the PGA Tour.
"I know that I'm in a good spot," he added. "If I think about 2015 through 2020, that five-year stretch, I seldom had a realistic chance to win a major championship.
"So I'd much rather have these close calls. It means that I'm getting closer.
"But yeah, absolutely, I'd love to be able to play the golf and get one over the line, but as soon as I do that, people are going to say, well, when are you going to win your sixth? So it's never ending."
