eating disorders can show themselves in a variety of ways, so yes, it's possible. however, since you're experiencing pain and nausea, i would definitely recommend you have a regular medical doctor check you out for gastro/intestinal disorders, food allergies, gluten sensitivity, etc., first and foremost. if there doesn't seem to be a physical reason behind what you're feeling, then you might want to talk to a T about your relationships to foods.
i really hope you feel better soon!