I would be more worried about the gorging and purging. It's very unhealthy and can lead to serious problems if left unchecked. If it's something that happens often, it might be good to seek help to stop it. If it was just a one time thing, then focus on healthy eating and acitivty. Our weight naturally fluctuates a couple of pounds al day long. Protein and high fiber foods help us lose fat better than any other food groups. Make sure you get enough protein to maintain your lean muscle mass. The more muscle you have, the more calories you burn at rest, the easier maintaining becomes and losing. Take care of yourself.