When I started my teen years (12-early 14) I also felt the same with my mind. I was always depressed. I cried about anything and felt I was invisible to everyone, or that everyone was talking about me behind my back. Sometimes I felt good, but the majority of times I felt reallt alone, even if I've always had friends. I slowly learned how to forget about it. Make your mind busy. Learn a new language (this works, memorizing phrases in Japanese can distract anyone, lol), or try a "violent" sport like kickboxing or boxing, it helps blow off a lot of steem. I still get depressed, but it's a very rare thing, and if I do, I put a comedy show or something. I'm still boxing (i also do kickboxing, but i like plain ol' boxing more). Just distract yourself.
With my body is a different story. Being Puerto Rican, I'm blessed with a J.Lo butt, and my aunts were very busty, and so am I. I didin't mind it at first because I felt sexy, but I started doing more sports and physical exercise, and I've gotten very (not TOO MUCH, though) muscular. It's worse because I'm only 5'2 tall, so I look weird. Sometimes I feel I look ugly, but I don't let it get to me. I wear "skimpy" (I put the " because skimpy clothes in the U.S. arent skimpy here because its sooooo damn hot here) clothes and I dont mind, but sometimes theres a little voice going "youd look like a guy if it wasnt for your boobs and ***". I feel comfortable with my body, but like anyone else, I get insecure sometimes, the trick is to ignore it. We're all different. THus no one is truly perfect.
Hope I helped somehow

"Regardless, I have always, and will always, succeed."