Its impossible to say, 'bulimia doesn't make you thin' or 'bulimia isn't about losing weight' as every case is different. You can get purging anorexics, ie people who eat very few calories but purge them, and then lose weight. Or you can get compulsive overeaters who eat massive amounts of calories, fail to purge all of them, and end up gaining weight.
The OP sounds like she is using bulimia to control her weight, but there may be underlying issues as to why she turned to bulimia in order to do so. A surprisingly large amount of people make themselves sick at one point or other in their lives, in times of great stress, desperation or low self-esteem. But if it carries on, it is a huge risk to be taking.
I am bulimic. The things that worry me most about bulimia are not being found out, or the fact that it really harms your teeth and oesophagus in the long-term.. Those are minor. There are three things that really terrify me.
1) Instant death from heart attack caused by a sudden change in the amount of electrolytes in your body. If you feel shaky, depressed, dizzy, tired, weak or anything similar after purging, then that is what it is, and you should be worried.
2) Gastric rupture. The combination of eating large amounts, or just the repeated stress on your digestive system can weaken the gastric wall, causing rupture. In the worse cases, this can be your stomach literally bursting, causing a horrible death. If you have digestive pains, or your gut hurts after purging, you should be worried.
3) Death because of internal bleeding. A lot of bulimics throw up blood. In most cases, this is because you scrape the lining of your throat with whatever you're using to purge. However the lining of your throat is extremely thin and if you purge violently enough, you can do yourself a great deal of harm.
Basically, you can't deal with this all by yourself. Bulimia is addictive. Extremely addictive. And it is as much of a killer as any other disease. Like you, I am aware that I have a problem and I always said that I would 'do something about it' if it got really bad. But I feel dizzy and sick after purging, I have given myself a hernia from it and ignored it, and I throw up blood every time I do it. And I'm still not able to get better. Don't get to the same stage.
Go to your doctor. Normal GPs sometimes don't understand eating disorders fully so you must insist on seeing somebody who specialises in eating disorders, or insist on being referred to a trained therapist who can help you. INSIST ON IT. Don't get fobbed off. "I am bulimic. I have a disease. I insist on being referred to someone who is qualified to help me and I will not leave until you make that happen" should be your words if they try to make light of it.