Water weight or getting fat? please answer!?

k so i lost about 6 lbs because my stomach was all messed up for a few days. it stabilized and i stayed the same for a few days eating only small meals... then a couple days ago i pigged out for the first time which wasn't actually much but felt like a lot: a couple eggs, a bunch of strawberries, some rice and indian food. then the next day i weighed 3 lbs more. i figured it had to be water weight, right? then yesterday the same thing happened; i had toast for breakfast, along with an apple, some cottage cheese with fruit for lunch, and an enormous bowl of salad (no dressing) with a couple turkey slices) and now it says i'm another lb. so 4 lbs more than i was before...:( but i checked my measurements (with a tape measure) and it says i'm the same everywhere except my waist which has bloated up. so this is just water weight right? or is it stuff about to be stored into fat?