Over exercising is bad, and so is over eating. Perhaps, that’s why Buddha preached to follow the moderate path. Normally work-outs should make you feel rejuvenated and not depressed. You must look into your fitness regime. And, equally important is to correct your eating habits. There must be a fine balance between the two. There is a useful site about eating disorders and treatment, http://www.edtreatmentcenters.com/ . Check them out. Good Luck!