It's so easy to fall off the wagon, but so much easier to not get back on! You should be proud of yourself for making the move to get back on in good time. It's definitely a relief that it's only 2lbs, I've fallen off before and gained a stone and a half and it always feels like a mission to get back to where I was. But that's the best thing with 3FC. You can come back whenever and know that the support is just waiting for you.
All I'd say is not to beat yourself up about it, keep it moving and don't let a little slip up turn into a biggie