Don't feel bad about that. I have had many experts tell me that a cheat day, once per week is an ideal way to lose weight.
Your body is concerned about self-preservation. And once it realizes it is losing weight, it begins to fight you. A periodic 'cheat day' tricks your body into thinking that everything is back to normal and it quits fighting your weight loss once you resume the diet.
A cheat day is also a great mental help, not to mention better for your social life if you want to enjoy a resturaunt meal with friends or a cookout with the family.