Hi there!!
I just wanna say you're doing so so well. Really really well!! I think you should be really proud and not let your weigh-ins dishearten you if they aren't what you'd like them to be. The thing is, even though you haven't had as much time to exercise with school, if you're still eating a low calorie intake, you're not going to put on weight due to lack of exercise. Do you see what I mean? The fact that you're a few pound heavier could be any number of reasons - you may have turned some fat into muscle, and muscle weighs more than fat! But this is a good thing so don't worry.
Also, have you still been having a lot of water even though you've been exercising less?Chances are (if this is the case) that you just have a higher level of water in your system as it's not be released from your body as sweat! (Grim, I know!)
It could also be anything from how you were standing on the scales, what time of day it was, where in your monthly cycle you are or even for toiletry reasons! There could be a huge number of reasons so really, don't worry yourself. I'm sure in a couple of days you'll find yourself a good few pound lighter!
So yeah, really don't get disheartened and be proud of what you have achieved!! I would be shouting from the rooftops if I had lost the amount you have =)