I did that this weekend too, I was proud of myself for weighing 169 (and getting out of the 170s!!) and then I ate Wendys on Saturday, and a huge dinner on Sunday, and snacked all weekend long. Didn't count calories, didnt' exercise.
I weighed 172 this morning! SO... I'm up 3 pounds, haha! I think it is just part of it- something I keep reminding myself is that I could be carrying some extra water weight from eating poorly this weekend. So I'm choosing to drink a ton of water and eat high fiber and protein this week to flush my system and help me poo a lot, haha, sounds weird I know but it DOES help.
That's another thing, if you weighed yourself and you haven't pooed in awhile, that may not be your actual weight. Just saying, haha...
Just jump back on that bandwagon- remember that you didn't gain this weight overnight and you won't lose it over night, but you CAN change the direction of the scale with each decision you make. So just rededicate to making good choices and you'll see those 2 pounds gone again in no time. Just make the choice now that that 2 pounds WILL NOT become 5 or 10 or whatever, but that instead that 2 pounds will melt away ASAP because you've worked too hard to have to start all over again!