Hi Nicola, actually this thread was started by Emily and we seem to have hijacked it, but I am sure she won't mind one more !!
Don't beat yourself up, I personally have had a lot of day 1's that didn't make it to day 2's, take it that you have learned something valuable about your eating habits and draw a line under it, today is a new day, the very most important thing is to get back on the wagon today, forget yesterday completely.
The first few days are hard, but after day 3 in finished you can give yourself a massive pat on the back and know that it gets easier from then on in, do you have any goals in mind?