The unseeded Australian advanced to the Wimbledon final when Rafael Nadal withdrew from the tournament because of an abdominal injury.
He says the news caused him to have a restless night.
"So many thoughts in my head about a Wimbledon final," Kyrgios said. "That's all I was thinking about."
Kyrgios will face either six-time champion Novak Djokovic or Cam Norrie in Sunday's final. Norrie is playing in the semifinals of a major tournament for the first time, but Djokovic has plenty of experience at this stage.
"That's where Djokovic has the advantage from the get-go. He can draw from experience, he's done it so many more times, he knows the emotions he's going to be feeling. I don't know that," Kyrgios said. "I don't know anything like that, so ... It was just all running through my head, every little thought, and I just slept really bad."