Is this a horrible snack for already eating 1200 calories? (easy 10 points!)?

I think that it is fine. You ate carbs, that's why you are feeling this way. It may feel as if you're bloated and fat but it will p. You're doing way beyond a normal 17 year old does so you are fine!! Stop worrying about it and take a rest. You're doing great girl, best of luck!