vent

I'm going on a massive holiday in a couple weeks. I don't feel comfortable in my own body at all, and so I'm trying to go to the gym to lose weight. My parents said no because I should feel comfortable already, but how am I supposed to go to the beach (which I really do) if I don't feel comfortable wearing a swimsuit? I had a 20 minute screaming match with them, and my mother hit me. They left and now I'm home alone. I don't know what to do anymore.