Hello~Have you been under an abnormal amount of stress? This can sometimes cause what you are experiencing. What were your blood sugar levels? Did he do an A1C? I am just curious because your symptoms do sound blood sugar related, but then again, the body is a strange (but marvelous) machine, so it could very well be something else.
Does the doctor feel the amount you are eating and drinking is abnormal? Going to the bathroom frequently after a lot of drinking is probably not uncommon. And are you also talking about bowel movements after eating?