What is the likelyhood of me getting my periods back after a yearlong battle of anorexia?

Thats something you should discuss with your doctor. They will be able to give you a more accurate answer then us. I am glad you are no longer anorexia and on healthy path. As for you still not eating sometimes for days, just try and keep munching on fruits and veggies. Even during exams, just try and eat cheese and cracker or anything, because with all that studying you are going to need the energy. Your plan for staying healthy after exams sounds great! Just remeber to ease yourself into exercise and don't go full out until about a month.