I try to think, "Is this thought helping me or hurting me?" If that does not work then try to analyze the thought, challenge it. Is it actually real? Am I considering both the good and the bad, or am I just focusing on either the good or the bad? If I am thinking about mistakes of the past, were they really mistakes or did I make the best decision I could at the time? If you cannot get rid of the thoughts, thinking about both the good and bad can often put them into perspective. Then think of the catastrophe scale. If death were 100, being paralysed is a 80, living on the street destitute a 60,then how bad is the mistake I have made in the past? Is it really as bad as I am thinking?

Sometimes it works, sometimes your just going to have a bad day and tomorrow will be better...