You planned out your meal, snacks and treats too. So you “shouldn't” have felt deprived and you “shouldn't” have binged on that pizza, but—guess what—you did. It happens. Making a plan helps, but it doesn't ensure total success. What you really shouldn't do is throw in the towel and go on an eating free-for-all.
The key to overcoming slip-ups is to forgive, forget it and get right back on track. Guilt begets more bingeing; don't give in to that. Don't fall into the splurge-and-then-skip diet—it's not healthy or enjoyable and you end up hungry and guilty. Besides, punishing yourself with tiny meals doesn't inspire healthy habits you can keep and enjoy throughout your life. Plan a week's worth of delicious calorie-controlled dinners so you can stay satisfied and happy.