You didn't do anything wrong ! One meal or even one less than perfect day or week of eating will NOT make or break your healthy lifestyle. Don't associate food with guilt. that's not healthy. There are going to be days you eat more than others for many different reasons. As long as you eat right most of the time and watch your portions, there is absolutely no reason you can't have some chicken cheesteak once in a while.
Spark People has never been about deprivation. It's all about moderation and portion control. So, as long as you don't eat cheesteak every single day, once in a while is okay. Did you enjoy it ? If you enjoyed yourself, what's wrong ?
The fact is, you don't have to be perfect to be healthy. I can't imagine living a life where I wasn't allowed to eat something because I was afraid I'd gain weight. that isn't healthy either.
What to do ? You just eat a little more mindfully for the rest of the week. You don't beat on yourself. You don't punish yourself with extra exercise either. You ate the food. You log the food. You move on.