"All the love and all the support I have made to realize that I am more than my results and my gymnastics, which I never really thought before," Biles writes on social media.
The 24-year-old is one of the biggest stars in the Olympics and came to Tokyo to win five golds.
But already in the first final on Tuesday, she got into trouble.
Biles broke the team final after a failed landing in the initial moment of jumping and the USA had to settle for silver behind the Russian team.
Afterwards came the explanation:
- It did not feel like I had much fun.
I wanted to take part in these Olympics for my own sake.
I came in and felt that I was still doing it for others.
It hurts my heart that the feeling of doing what I love has been taken away a bit to make other people happy, Biles said.
Simone Biles was praised around the world for her openness about a topic that few elite athletes want to talk about.
Biles herself said that she was inspired by another superstar who talked about her mental illness - the Japanese tennis player Naomi Osaka.
The day after the team final, the American Gymnastics Federation announced that Biles is over the all-around final.
It is unclear whether she will compete in the branch finals, which will be decided Sunday to Tuesday.