Yes, it is possible to have Bulimia Nervosa and still be overweight. As long as you continue vomiting, you feel no need to be responsible for overeating. This is why it is imperative that you stop vomiting. You need to become more in tune with when you are hungry or full in order to be rid of your eating disorder. Staying on a diet will not cause you to get well. You have to teach yourself to eat only when you are physically hungry. People suffering from Bulimia will stuff themselves with food in order to avoid psychological discomfort. You need to learn how to face up to and endure unpleasant things.
A person who has eating binges, but does nothing to get rid of the calories, is said to have Binge Eating Syndrom.