Bad few days....no motivation to follow the plan

I've had a bad few days with the weight watchers plan. It all started last thursday, I missed my weekely weigh in due to a work commitment. Bad mistake decided to get pizza hut and totally rigged out with 3 pieces of stuffed crust pepperoni lovers. Since then I have not followed the plan at all. Well it really started Wednesday I ate McDonald's due to being absolutely starving and with a work commitment until 10p. My boss bought dinner for all of us there. I've eaten fast food every day since then. Can't find the motivation to start up again. So disappointed about this....