What is wrong with me?

I think I have some sort of trust issue, or some sort of anxiety, but I have issues tlaking to people about personal things. When I got my first period, I couldn't tell my mom. I tried, I called her on the phone, I remember it distinctly, but I chickened out. I went for two years without telling her until she finally figured it out. Another example, I never talk to anyone about crushes that I have, and if somene asks me, i get extremely defensive, or I go completely silent. My friends will talk about some cute guy, and I will just be sitting there, silent. I am not close to anyone. I mean, I have friends, but I don't have anyone who I can tell these things to. I can talk to people about it if I am not looking at them directly, like on a computer when I have no idea who they are, or they don't know me. But I can't talk about personal things with people who I know well. I am not a very happy person either, I am somewhat depressed, and I try to tell someone, but I can't. It is like something is physically stopping me. I really, I jsut want to know how to fix this. What can I do? What can I do that I will be comfortable with doing?