Despite what John Mayer says about it, (side note: I love that song by the way and agree with its sentiment...but this is not what I'm saying.)
Belief is everything. It is the core within you that starts the fire. Everything extends from there. That makes it all the more important that you are careful what you believe. Question every belief that doesn't allow you to be your best self. Embrace and cultivate the beliefs that invite you to live well, love purely (that includes yourself) and do good. In time you will break out of the shell of self doubt you are encompassed about in now and arise as the amazing creature you were always intended to be.
-that one was from me.