Eating disorder or not you're definitely underweight. For a 15 year old of your height, your weight is at the 17th percentile, which is technically in normal range, but the very low end of it. Your BMI, on the other hand, is 17.1, which is low enough to meet the diagnostic criteria for anorexia.
When you say you can't stop yourself from eating, do you mean from eating a normal amount or from overeating (in your case that would be getting significantly more than 2231 calories, based on your height, age, weight and activity level)?
I'm not a doctor, but my best guess would be that you have anorexia, or possibly ED-NOS (eating disorder not otherwise specified), leaning towards anorexia. It's wonderful that you want to stop doing these behaviors, because the younger you are, and the less time you've had an eating disorder, the easier recovery will be.
Ideally you would start by talking to your parents about this, but if you don't feel comfortable doing that then find out confidentiality laws in your state, and start seeing a counselor. Eating disorder treatment for a teenager needs to involve a medical doctor, a counselor and a nutritionist, and probably your parents as well since in most households its the parents who buy the groceries and cook meals. If you can't find resources that work for you, try looking for an EDA (Eating disorders anonymous) meeting in your area. Even you don't like the meetings themselves, the people there will be able to help you find resources.