I was anorexic and bulimic for a few years from about age 16 - 20. I refused to go to the Doctor and after a few years of eating less and less I hit "rock bottom", which for me was when I stood on the bathroom scale one day and saw that I weighed 4 stone. That moment was what did it for me. I knew instantly that I was not in control and that I was in danger and there and then I decided I wanted to change course. I started eating properly, joined a gym and started to and take pride in making my body as fit and strong as I could.
I'm not sure that I am "cured" even now many years later but I've eaten good healthy food since and I've managed to keep my BMI just within the right range.
Good luck. If you need support, ask your GP to refer you. There is help out there nowadays that wasn't available when I was young.