Hmmmm.....
You have to climb straight back on the wagon this morning, drink lots of water, go for some long walks, and have a two or three pp days to make sure you go back into weight losing mode.
But you might also like to look at the things which triggered your jump off the wagon.
1.) Going out a friend to drink.
Could you have suggested meeting for coffee instead? Or to the cinema? Or bowling - something where drinking alcohol is not the obvious focus?
2.) Drinking alcohol. Any alcohol - even vodka - will hot you hard if you are in ketosis, and make it much much harder for you to make the right choices later in the evening when the crisps and chips and kebabs and tequilas are being slapped down in front of you.
Worse - Alcohol will tip you straight out of ketosis - and make you feel ravenously hungry.
So if you really want to go out to a pub, club or party - drink water or diet coke only.
3.) Food. It's really too late by then. But could you have chosen something more Dukan-y than chips from the menu? A burger (and left the bun)? A steak? Chicken strips?
4.) If its really hard for you to stay on the wagon - then be anti-social for a while. After all, you have so little left to lose, and your original goal date was only two weeks away.