I too used to do this let one bad day lead to another, then a week etc, and constantly saying ie 'i'll start diet again on Monday' but now I draw a line under that binge, that meal and continue on plan and its working for me. My losses are slow but I am beginning to accept that too.
I don't call it a diet either as I swear the second my brain thinks 'diet' I want everything I shouldn't have. I consider this a new way of healthy eating. There will be blips the odd mcdonalds, the odd glass of wine, but this time they will be just the odd one and just that 'a blip' I am finding it much easier to stick to plan with this way of thinking.
I also bought a self hypnosis cd which I swear is helping me to stop the snacking and craving. I adore chocolate, I love crisps yet I don't fancy them anymore, so to me the cd must be helping. It said to listen to it every day for 30 days and I think its been a fortnight, but I no longer seem to crave the unhealthy foods so will continue to listen to it as apart from anything else I find it so relaxing at the end of a stressy day to chill out and listen to it for 30 mins.
Now if I fancy something sweet I have one or even two alpen light bars usually the caramel ones as very sweet and seem to stop the sweet cravings for me, whereas before I'd have had 2 or 3 choccie bars at least.
So yes I draw a line under that action rather than that day now, moving forward straight away that way the consequences are minimal. I also eat lots of melon and strawberries and kiwi and drink tonnes more water