i used to feel that way too about a years ago.
i think that the most common reason that people don't have enough confidence in themselves is because they often compare themselves to others.
if you are thinking that way, you will never be satisfied of yourself, because, no matter how good are we, there will always be someone better than us. and
just be yourself and don't think about what other says (but maybe sometimes it's necessary to take some advice from others people too
). you really deserve what you can get.