Ditto what Trus said.
Stuffing up is one thing, but giving yourself too much of a hardtime can lead you into a nasty downward spiral. Remaining positive is the way to go.
Yesterday i had a shitty moment. But this site helped me stay strong and I got through it without caving in to the cravings. There's a lot to be learnt from reading around other people's diaries.
Have you ever read the book When Food is Love. I can't remember the name of the woman Maybe Rowena someone. This book helped me deal with some of the guilt feelings around overeating. I read it ages ago though.
Do you know why you needed to eat after dinner the other night? It might be worth looking at that. Did you eat enough for dinner? Or was something else going on? What i did yesterday when i got my emotional craving was eat something else instead - fruit and yoghurt. I wasn't sure if it would stave off the feelings but because i tried to distract myself with other things, it seemed to all add up to something that worked and then the moment (it was a few hours) passed. On the other front, i got zero work done because of all that emotional mess but at least i was able to avoid caving in to cravings.