If you ever get nervous or anxious or beat yourself up for eating something "bad" or going over your calories, pay attention because this is important. First off, there is no such thing as a "good" or "bad" food. "Right" or "wrong" food. "Healthy" or "unhealthy." There is only food. And, yes, you can sometimes eat too much (or even too little). But there isn't a single food on this whole earth that is inherently good or bad.
Second, progress comes from consistency NOT rigidity. Often times we'll eat something and immediately start beating ourselves up about it. We'll think we’ve failed or ruined all of our progress and we have to start all over again. But, in the same way no one has ever become skinny off eating one salad, no one has ever got fat from eating a doughnut (or doughnut or pizza or ice cream or whatever). "Progress takes time. Progress takes patience." And the sooner you realize the key to successful dieting lies in a flexible approach the sooner you will remove all nutrition related stress from your life.