[CAUTION: ANOREXIA/BULIMIA TRIGGER WARNING]
No, this isn't an eating disorder. An eating disorder is when you're willing to do anything to lose those last five pounds... And the next five... And the next. A good bit of it is about thinking, which can exist before and after the eating disorder itself. If you're genuinely not hungry, and you don't necessarily want to keep from eating, then it's not an eating disorder. If you and a person with anorexia sat down to the same meal and ate the same amount, only a couple of bites, where you would say, "Oh, I'm so full," the anorexic could very well say, "I'm starving, feel that hunger clawing at my stomach, feels so good! Tomorrow I'll eat even less!" or "Oh, I'm so stupid! I knew I shouldn't have eaten so much, I'm so bloated! That's all going straight to my thighs. It's back up to the bathroom for me, quick purge and then another hour of exercise. Gotta burn those calories up."
I think this may be a blockage in your intestinal tract. Are you constipated, sick or stressed, also? I would suggest going to the doctor immediately, and especially getting blood work done as well. This could be very serious, especially if you're losing a lot of weight. If you don't act soon, there could be complications.