How does one deal with eating disorders /fit/?

>17
>fell in love with a straight guy
>maybe he'd like me if I was thinner, I look hideous (BMI 20)
>became best friends with Ana, lost weight like I was starving, haha
>ugh I ate slice of bread all day, I'm a disgusting fattie, tomorrow I eat nothing. maybe even the day after that.
>do this for over half a year
>BMI 17 later 16.

>20
>still constantly anxious and depressed
>food fills me up though. It eases the pain for a while. Maybe just a bite more. just a little. okay maybe more. mooore
>feel regret and shame
>go to the toilet and puke it all out
>I'll never binge eat ever again, I swear. oh my god, is that a bar of chocolate?

>23
>feeling completely dead and empty inside
>start compulsively overeating
>end up with BMI 32
I mean, what am I to do? I started dieting last year, went all right for a couple of weeks, but then my best friend Ana decided to visit me once again. Lost 50 lbs in 2 months. Everything went okay for a while, then I started binging again, abused laxatives and puked in the toilet regulary.
Returned to my original weight 11 months later. I'd start dieting again, but I'm almost 100% sure it'll end up triggering another anorexic phase. Short of hanging myself or moving in an insane asylum what can I do to fix this mess?