Hi!
Have you done any soul searching as to why you have this troubled relationship with food? You could be trying to control your life through controlling your food intake, however little or much it is.
Your weight may still be too low but you may look healthy. I think this is what bothers your Dean and eveyone else. Your well being. And this is what you must try to achieve. Live healthily. Eat healthily , take any physical activity and be happy. If they see that you are trying, no one will stop you from completing your studies.
But first ,you must think why you are doing what you are doing, because even though you say you are binging in order to put on weight, you sound as if you resent this. If I am right, try to find out why. The answer to this could spell the end of your problems. Therapy sessions will definitely help you if you stick to them and believe in them.
Good luck