When I feel like I'm failing, or a disappointment or will never reach my goal, I say to myself:
"Ever tried, ever failed. No matter. Try again, fail again. fail Better"
It's by Samuel Beckett, the playwright. It sounds odd, I know, but it reminds me that no-one in the world is perfect. We all make mistakes and sometimes take the wrong road but the important thing to do is pick yourself up and try again, if you fail again, no matter, just keep on trying.