Four big things that can cause bed wetting: stress, exhaustion, illness and food/chemical reactions.
If it is exhaustion, the best thing for you to do is to help her to the toilet without fully waking her up (I usually did this just before I went to sleep around 11 or midnight) and encourage her to pee then. After a while she will be able to wake herself up again during the night.
It's possible that she is having a food or chemical reaction--keep on the lookout for new foods she hasn't had before--especially things that only show up during the holiday season. Also constipation can cause loss of bladder control--if she is struggling from holiday induced constipation, encourage her to drink more juices etc.
If your daughter is starting or recovering from any illness, help her ride it out--remind her it's not a big deal, but if she can call for you to help her to the potty during the night you can take her.
Find out if she is stressed about something--new siblings, changes over the holidays, arguments with friends/family . . .
The biggest part is not to stress about it (if you are stressed it'll lead your daughter to have more stress . . . .) try to find the cause and eliminate it or do some preemptive "pottying" on days you know she will be more likely to wet the bed (for example when my daughter has had a really busy day and is more likely to sleep really deeply, I will carry her to the potty while she's sleeping and have her pee at night or early in the morning (around the time she would normally wake up).)