I know I have suffered from this in the past. I would lose a big tournament. Then, I would relive that fateful match and visualize all the different things that I could have done. After my first world championships, I played back my matches in my mind for months!
All this did was make me miserable. What I should have been doing is what winners do, which is to relive my victories. You want to relive your success stories over and over. Let them inspire you to do more, train harder, and grow.
Winners keep their mind focused on success, while losers stay stuck on failure. Losers fear failure. All of their decisions are based on avoiding failure. Be a winner and always keep your mind tuned to achieving success.
If you find you are pitying yourself or dreading failure, snap out of it! Make the decision that you are a winner and you will only ponder about success.