Sounds like hypoglycemia to me. Try keeping your blood-sugar levels steady by snacking frequently-- every 2-3 hours is ideal. Sweets don't count. They cause a rapid rise in blood sugar followed by a hard crash, leaving you craving more sugar. Carry a ziploc bag in your purse or a little cooler in your car with whole foods like almonds, natural trail mix, baby carrots, whatever you like. And always stay hydrated. You should feel the difference within a day or two.
If not, visit the doc to make sure it's nothing serious.
:-)
I don't think you have an eating disorder. It sounds like a medical problem. You don't say how high and how low your blood sugar goes. It sounds like you need to check further into hypoglycemia or diabetes. If your doctor can't help you, ask for a referral to an endocrinologist. You need an A1C test as well as an OGTT to see how you react to sugar over a period of a couple hours. Be persistent, don't just accept a random blood glucose check which is meaningless.