Sometimes a person suffering from post-holiday syndrome or post-Christmas blues can behave in an erratic fashion for the initial weeks after the holiday, doing things like waking at night and sleeping during the day. Realize that the change back to a normal routine is disruptive and ease yourself back into it.
Confirm your next holiday or vacation. It can be motivating to pinpoint the next time you'll be off work. Look at your calendar and figure out your next escape. You might look for the next three-day weekend, national holiday, or confirm your overseas vacation three months away. Doing so can help you keep your eye on the ball at work.