please don't beat yourself up. there are many techniques to be used for messin' up. when i quit smoking, i cheated a few times, and regretted it, just as you are now. with this woe, i've been tempted. the one thing i keep telling myself is that if i really want it that bad, then wait and i can have 2 in an hour. by the time the next hour comes, i don't even want it.
just remember that the most rewarding things are what you worked hardest to achieve.
we are all here for you. good luck, hth
bren