Am I hurting my body if I have an eating disorder?

Yes, maybe. An eating disorder can lead to nutritional problems and imbalances that can harm your body. Please see your doctor for help or referral for treatment of your eating disorder.
Possibly. The key is in the words "eating disorder". If eating habits cause problems of any kind it is likely a "disorder" and can be "hurting" the body. Anorexia causes medical issues in it's extremes including electrolyte abnormalities, damaged kidney function, cardiac irregularities and even death. Bulimia isn't much better. Erosion of teeth, GI problems, electrolyte issues stem from binging & purging.