This is a difficult time of year, especially if you have lots of family commitments. It's really hard for writers. We are used to peace and quiet, to having the house (or at least our writing room) to ourselves, to having our brain to ourselves. Suddenly, at Christmas, we have a million things to do, including cooking, shopping, cleaning up, etc - and then we have visitors. People in our house, wanting stuff. People of all ages from 2 to 92, demanding conversation, food, your attention. Where did your headspace for writing go? Arrgghhhh!
You have two options. One is to give in, to allocate however many days it will take to accomplish all that family stuff and simply go with the flow. Talk for hours to old rellies and little kids, prepare and eat and clean up tons of food, drink and eat too much and fall into bed. Read sometimes if you get a few minutes of peace. But give up totally on writing. It's hard. You were in the middle of something great. Your brain had moved into holiday mode and the writing was going well. But ... it's Christmas and you had to do the family thing or be called 'hostile' or 'inhospitable' or 'downright rude'.
The other option is to squirrel away your hours. One or two early in the morning before everyone gets up. One or two late at night after they've all gone to bed. One while they went for that family walk along the beach, and you said you'd be along soon ... One when they were all snoozing after lunch. One when they were all arguing about who made that fab Xmas cake back in 1992 and no one noticed when you crept away. By the time New Year arrives, you discover that you managed about 12 hours of writing, simply because you were determined to, and why the heck should you be on call 24 hours a day?
I'm kind of lucky (or not, if for you, Xmas is totally about full-on family for days on end, the more, the better). Most of my family live a long way away, and if I can't afford the air fares, Xmas in our house is fairly quiet. In fact, the whole Xmas period ends up being quiet. Great phone calls, but not a whole lot of socialising and having a house full of visitors. So I get to read a pile of books I've been saving, and I get to write. But I only write if I feel like it, because like many people this time of year is actually the one time when I can say STOP, close the door, turn off the computer, put my feet up and relax.
It's also a great time to re-energise. I love to do this by reading lots of books, seeing lots of movies (looking forward to "Bright Star" in particular), going for quiet walks in the bush, and sleeping. Nobody can work 52 weeks of the year, and really feel a constant supply of energy is available. So if you can't write at the moment, at least think about how you might re-energise your writing brain/imagination for the new year. And have fun!