I would say its EDNOS (eating disorder not otherwise specified). Basically anyone who has disordered eating but does not fall into the specific categories of anorexia and bulimia would be considered to have EDNOS.
Most people who have eating disorders are actually in this category. In order to be considered anorexic, one must have a BMI below 17.5, and have stopped having periods...someone may be an extremely low weight but still get periods for example...so she would be EDNOS.
The diagnostic criteria for bulimia would be binging and purging at least three times a week for the last 3 months. So depending on how often you purge, you are either bulimic or EDNOS.
Having said that, it doesn't really matter what category you fall under. The fact is that you do have an EATING DISORDER. People die not only from anorexia and bulimia, but also EDNOS....and as you probably know purging is doing quite a lot of damage to your body...it damages your stomach, esophagus, mouth and teeth, and causes eloctrolyte embalances wich can lead to cardiac arrest and death.
Also...ednos can often just be the beginning of full blown anorexia or bulimia....so if you don't get help now it could definately escalate into something a lot more serious and trust me, it is NOT fun trying to recover from something that completely takes control of your life like an eating disorder.
So even though you think its probably not htat big of a deal right now (that is, by the way the voice of "ED" telling you that so you don't get help when you should), seek help. Talk to a parent, close friend or someone you trust, or go see your doctor and he/she can reffer you to a psychologist or therapist.
I know it is sooo hard and embarrasing to tell people, but it is the first and extremely important step towards getting better.
All the best