I think you'd do well to think of this in terms of disordered eating, rather than worrying about what eating disorder it is. MOST people with eating disorders actually fall into the EDNOS category -- Eating Disorder Not Otherwise Specified. That's what I'd call you, too, because you meet many of the criteria for the binge/purge subtype of Anorexia Nervosa, but your weight is above 85% of normal, which is one criteria.

So, the hospital told you to lose weight, and then just left you to your own devices? Shame on them! What you're doing right now is very harmful to your health, and really will screw you up. I strongly recommend that you talk to your doctor about all of this, and see about getting a referral to a therapist and to a dietitian for nutritional counseling.

Just as a general rule, you should NEVER eat fewer than 1200 calories per day without close medical supervision. That sort of thing is reserved for morbid obesity, not for someone in the "overweight" range.

Good luck.