I don’t know who its is and i need help

I get cyberbullied by people and I don’t know who it is because it is on an anonymous website they call me fat and ugly,say I’m weird and cringy, call me a lesbian, say that my boyfriend is cheating on me, say that I’m not worth it cause I was a mistake. My mum found out but I told her I was fine but I’m not I wanna kill myself and go on a diet just so I can be good enough for them. I need someone’s help I don’t know what to do I hate myself and this world!!!!!