So you had a good holiday with lots of lovely food - well, good for you. That's what holidays are for!
I will bet you that 90% of the people at your SW class have put on weight on holiday - we all do it. I certainly do.
Go and get weighed, tell everyone about the good time you had, have a good laugh about it, and then get back to the plan.
The gain will be gone in no time, but your holiday memories will last.