I read about a strategie how to cope with my anxiety attacks and I worried about "what if it won't work" (future) and "No matter what I do, it won't work" (past).
When I was very young the songtext below was I favourite of mine. But I seldom live by it...
Fill your heart with love today
Don't play the game of time
Things that happened in the past
Only happened in your mind
Only in your mind
So forget your mind
And you'll be free...