It won't make you feel better. Well, maybe for about 5 minutes until the guilt sets in - and then you'll be really cross with yourself.
The best thing to do is find yourself a distraction. Get in the bath, paint your nails, go for a walk, phone a friend, drink some water, find a good book to read...
What's your favourite thing to do (other than eating )? Can you do that / arrange to do it tomorrow so you've got something to look forward to?
We're all here for you if you need us. I doubt there's anyone here who hasn't felt exactly the same at some point on this diet (and every other diet, come to think of it )