Eating disorder, help?

Okay, so i think I have an eating disorder. I feel guilty after I eat, I throw away the food i'm supposed to eat. I throw up sometimes, I exercise after I eat, sometimes I don't eat. Well it's shitty. I've been doing this for a month, I try stopping, but i can't help but feeling guilty after i eat. And the purging, it's relief. It's like cutting, I do that too. But now I'm doing it more as an alternative to throwing up. We;; I'm just screwed now. My cousin found out about it, she wants me to tell my mom. To be honest, I kind of want help. But I'm scared of telling my mom. Can you guys help me out a bit? How should i tell her? when would be an okay moment to tell her?