Is the other half pizza gone? If not get rid of it. Do some exercise and just set ahead in the proper direction. Dwelling on your mistakes makes them seem bigger and more important than they are. There is no mistake, you make today, that screws up everything you've done. And there is no mistake that you can't fix. Nice thing about losing weight!
Plan for a better day tomorrow. have you been to the support forum? There are now daily threads about planning to have a nearly perfect day tomorrow.
One thing I have learned, one half a pizza or a block of chocolate or a tub of Ben and Jerry's is not going to make you regain half a stone (7lbs) if you only do it once.
Draw a line under it and move on.
Start planning for next weekend now, if you are the sort of person who tends to lose the plot at weekends. Personally I find the weekends easier than during the week, so all my planning has to be done for 5 days rather than 2!
Allow yourself limited quantities of the things you love occasionally. If you are able to do that without bingeing. Like two slices of pizza with a big salad once a week.
Preparation, planning and perseverance are the keys.....
It was just a one off, normally Im good and can lose weight while eating very small amounts of chocolate and the things I still like. Yesterday was terrible I didnt exercise either. Being upset made it worse, missing a day of exercise wudnt have matter a great deal (well not until I ate the half pizza anyway!).
Oh well, start the week a fresh, I still have my aim of the End of April to lose the 28lbs by the end of April. Fingers crossed.