Sha'Carri Richardson Admits Feeling Bitter Watching Olympics

Sha'Carri Richardson says watching the 2020 Olympics from home was bittersweet ... admitting she was initially pissed to miss out on competing, but it ultimately helped her move on from her marijuana suspension.

Richardson -- the fastest woman in America -- is set to return to the track in the Prefontaine Classic this weekend ... her first race since being punished.

Before making her big comeback, the 21-year-old explained what it was like having to experience the Tokyo Games from a TV instead of in person ... saying it was a bit of a mixed reaction.

"It was a moment of bitterness, but at the same time it was sweet," the U.S. track star told the "Today" show.

"Because, it just gives me more --…