How do u get out of a weight loss slump??

I just moved in with my boyfriend and the past month has been great, I've been doing exercise almost everyday, but the thing is that my munchies are just driving me nuts and if I'm home studying or watching TV with him OMG we eat a lot!! So I've decided to control myself, but I need to kick-start the weight loss again because I already gained three pounds and they are carrying me down!

I'm thinking of doing a one-day fast today, but I'm not sure that's a good Idea because my original plans for today were to swim a mile in the morning then later in the afternoon, since my boyfriend has decided he wants to workout too ( which is great!!) I was planning on training a little bit or if its sunny going swimming again, whichever he prefers, so maybe fasting today is not the best idea...

I don't know, help me out people! What do you do when you are in a slump???