Hey Perbain:
I've done the same thing too but ya know what? After about 3 months of this WOE I stopped altogether except for those miserable days right before my TOM (those are HARD to resist).
Yup, it is most important that you just forgive youself and move forward. Don't dwell on a mishap but congratulate yourself for doing so well and losing 12 lbs - that is no easy task lil' missy!