Actually, Reinhard says more than once in the book that overdoing it on S days is common and not to worry over excessively.
"..I have heard from plenty of people who anticipate this (binging) being a problem, burden themselves with weekend restrictions to prevent it, and then crack during the week because it's too much. S days are a necessary reward and safety valve." p. 100
"Don't Stress About S Day Overeating.
Overeating is going to happen on some weekends, especially at the beginning, when your body hasn't become habituated to eating less. Don't let this upset you too much." p. 102
"Keep the Focus on N Days.
The best way to compensate for an excessive weekend is not to add extra rules but to redouble your vigilance about adhering to the existing rules during the week. ..So don't be discouraged if you have a really excessive S day now and then. It will happen, especially at the beginning. Discouragement is the real danger." p. 102
Given that the holidays can be really challenging even for thin people, I highly recommend you just go back to N days as well as you can and commit to compliant N days from now throughout January, at which point you can reassess. Try not to put too much pressure on yourself to have reasonable S days soon. I don't know if I could have limited my S days sooner, but I didn't and I feel it has worked out well for me. (And I used to wait until midnight on Friday, open a bag of Hershey's kisses, and start chomping. That wasn't the end of it on a weekend, either. I took giving myself free rein seriously! But you won't necessarily be a wild as I was for as long as I was.) Realize that it takes time for your body and mind to adjust. Being in a hurry is the most common mistake most habit changers make.
A similar question was asked in October (and many times before, but that's the most recent one.)
http://everydaysystems.com/bb/viewtopic.php?t=8921
I know you know me from Sparkpeople. I hope you don't feel I'm bogarting the discussion. Maybe not so many people are online right now? Browse around some of the daily check in threads and testimonials. And remember OA used to have the motto: three meals a day and life in between. I know I've had to learn to put my attention on other concerns even after I've found more peace with food.
And on that note...