Do you feel like an impostor? Do you fear other people realising that you are not as good as your peers?
You are not alone, many people feel the same, and it goes away eventually. I know because I've been there, it is a really awful feeling that got me depressed and unhappy for months. But you can try to fight it!
This is an excellent document from the Geek Feminism Wiki, that I found thanks to pabs@, make yourself a favour and read it: Impostor syndrome.