sisters bf

So my sister has been dating her bf for two years now and he is an actual asshole. Lately he has been calling me fat and making jokes about it. When he does in front of my sister, she just sits there and laughs. She can obviously tell that it upsets me and I tell her that all the time. It's really getting to me. I get social anxiety a lot too and him saying these things have made me feel especially bad about myself. I try to box up all of my emotions and act happy all the time but today i couldn't. I had my first panic attach out of nowhere and my sister still doesn't care. I really hate my life.