So what youre asking is whether or not how other ppl perceive you is who you are....

Well, how others see you never defines who you are. Its how YOU see other ppl seeing you that defines you. What you think other ppl see you as is who you are because that means that is how you act around them. It may be a mask but until that mask comes off(in your case being less defensive and taking more risks) you will be the person represented by the mask. Ppl dont have ONE true identity, given the fact that they can change.

Personally i have a friend that has your same fear of being hurt, and the one thing that i keep recognizing in her is the fact that she will never live her life to the fullest, one full of regret.