What's Wrong With Me?

I have had a low self esteem about my body since i was 11, I hated myself so much that when i was fourteen i use to cut 1/2 inch slices in my arms. I went through different stages of eating disorders like extensive exercise, spitting, counting calories and just not eating in general. I trained my brain to know the calories in practically all foods that my brain is constantly analysing and thinking. Bulimia i thought was an easy way to cheat the hard work and binging purging became my life, it revolves around it so much so that my potassium level was 1.4 when they first admitted me to hospital, they pumped me full of so much potassium and it was the little concentrated bags that i was screaming in agony for the first three days, though no matter how much pain i was in i still thought about image and weight and all i could think about is how fat my arm was from getting pumped with over 10L of fluid in three days. I've been in and out of hospital 5 time in the last 5 months because i cant control myself. I tried to eat an apple the other day and i could make myself keep it down. Today I spent $100 dollars on takeaway and because i didn't want to be seen with so much food i ate it in the toilets at a shopping centre. I no longer have to use my finger or anything else to make me sick because it just comes up now without any strain. I need help but i scared of it. i want to know whats wrong with me!!! why do i have to do this to myself, why me why me why me. I want to go out to dinner with my friends, Go to the cinema with a boy and not leave just before the end to purge come back up and hope he doesn't smell vomit on you. I want to spend my money on cloths, movies big events rather than on food for the closest toilet.