I'd rejoin ASAP, while you're in the mindset. I know Christmas may not be an easy time and it's very rare that any of us are 100% on plan over the festive period, but if you're back at group and back on plan it might encourage you to make more sensible choices and not totally blow it.
Or the other option is to carry on as you are. Have the usual blow out at Christmas whilst SW falls to the back of your mind. And come January rather than half of the weight you lost being put back on, it could be a hell of a lot more!
I know which I would rather...
Also, I found this poem online. And I know I definitely wouldn't want to feel the way the narrator feels come January. This might inspire you...
Twas the month after Christmas,
and all through the house,
Nothing would fit me,
not even a blouse.
The cookies I'd nibbled,
the eggnog I'd taste,
At the holiday parties,
had gone to my waist.
When I got on the scales,
there arose such a number!
When I walked to the store,
(less a walk than a lumber).
I'd remember the marvelous,
meals I'd prepared;
The gravies and sauces,
and beef nicely rared,
The wine and the rum balls,
the bread and the cheese,
And the way I'd never said,
"No, thank you, please."
As I dressed myself,
in my husband's old shirt,
And prepared once again,
to do battle with dirt,
I said to myself,
as I only can
"You can spend a winter
disguised as a man!"
So-away with the last,
of the sour cream dip,
Get rid of the fruit cake,
every cracker and chip.
Every last bit of food,
that I like must be banished
Till all the additional,
ounces have vanished.
I won't have a cookie,
not even a lick.
I'll want only to chew,
on a long celery stick.
I won't have hot biscuits,,
or corn bread, or pie,
I'll munch on a carrot,
and quietly cry.
I'm hungry, I'm lonesome,
and life is a bore-
But isn't that what,
January is for?
Unable to giggle,
no longer a riot.
Happy New Year to all,
and to all a good diet!