JF, this happens to a lot of us... it can mean a few things.

1) the rebound weight hasn't caught up with you yet
2) you were due to lose it anyway (and you were - it's common to lose big during Induction, slow down a few weeks then *bam* start losing again)
3) you're dehydrated from the alcohol.

If the weight stays off over the next few days then I'd go with "2" or "4".

4) Your body is trying to tell you it would lose better with a few more carbs.

HTH
Nat