You're not the only one, trust me! I went off my diet for a whole week, and gained back the five pounds it took be two weeks to lose! I am still on level two at the moment but starting monday it's back to level one..I need to get a jump start again. I figure a few level 2 days won't hurt, just to use up a few items in the fridge that only I will eat like yogurt and soy milk.
We all just have to jump back on the wagon when we fall off, and look at each "mistake" as a learning experience.
A week of eating crap sure wasn't worth it to me!