Accept the fact that everyone occasionally fails, but see it as an opportunity to learn from the experience so you can do better next time. Being positive you can change your thoughts into healthy productive ones. It will require effort and and persistence but you're capably of both, right? It's also important to understand that you, and you alone, are in control of the thoughts that pass through your mind.Negative thoughts that arise in our mind should be cast out out by being optimistic in approach of life. Courage with which you have struggled against odds is your strength & ability to fight.