I understand how hard it is not to beat yourself up when your dieting/exercising doesn't go as you planned. I used to be the same way. I'd miss 2-3 days of exercising and I'd feel like giving up on
everything in life, and would quit dieting and exercising, insisting that it'd never work. You're only human so you WILL make mistakes and stumble. But, try to use that feeling of "oh I failed today because I ate that huge piece of chocolate cake" to fuel your actions for tomorrow. Ok, you failed yesterday, so be extra cautious today. Plan your meals out in advance and make SURE you don't get hungry enough to binge again! Also, reward yourself when you do well on your diet/exercise plan. If you have a good week, go out and do something fun or buy yourself a little something at the mall as a treat. Ok, enough blah blah blah from me

Good luck (again) and keep me updated!