If you are trying to build your confidence back up, don't stress yourself out too much about it: you'll only make any growing doubts about your place in the world worse. Only insecure people base their self-image on what other people think, so the first thing you have to do is to stop focusing so much on the opinions of other people. Stop trying to impress other people and start trying to impress yourself! Do something that will make you proud of yourself: and your ego will grow taller.