It's okay! You are tricking your metabolism!

The thing is if your net calories are down for the week, then you are not gaining! And not gaining is good too!
When I was away this past weekend I decided to not stick to plan but not to go completely crazy either. I kept using MFP even though I wasn't going to be eating healthy. I was quite surprised that Insomnia Cookies (a NYC cookie chain) was in MFP! I had bought two chocolate chunk cookies the first night, but after eating one, inputting it, and reading it was almost 300 calories, it hit me it wasn't really that great. One was okay at 300, but two for 600??? That just seemed crazy.
I guess my point is, if I go off program, I think I might just enter my food into MFP anyway and that might help me see how much I am really eating. If I hadn't input that one cookie into MFP, I would have eaten probably 6 or more over the weekend! It was only 1/2 block from where I was staying and I would have probably stopped in every time I passed to buy 2 or more!

So I think MFP probably saved me from eating 5 more cookies for a total of 1500 calories!