If you are traveling to be with relatives for Christmas, make sure that you take into account everything can take a bit longer when you are pregnant. Lugging heavy suitcases around might be easy-peasy normally, but not so if you are also carrying a load in your uterus! Take a change of clothes with you too, in case that first trimester pregnancy nausea comes back at you in mid air. It's happened to me, and it can happen to you, too. But the most important travel tip has got to be taking plenty of water with you. Dehydration, even in its early stages, is not something you want to deal with, and especially not while you are traveling. At the party itself, make sure to take some time out if you feel you need to. Lock yourself in the bathroom for a long bath or shower if you have to, and don't feel obliged to stay up longer than you want to.
If you feel the need to take a nap in the day time, don't feel guilty. Your body knows what it needs. Christmas foods tend to be rich and greasy they are not normally the best foods for pregnant women. If you feel like vomiting when you see or smell the meal your mom (or anyone else!) prepared, you can't help it. If you are traveling to celebrate Christmas with relatives, ask them to get plenty of fresh fruits for you in advance, or whatever it is that you know you will be able to eat. Finally, some people will say drinking a nice glass of wine (only one, though), is fine in pregnancy. But you should definitely avoid those raw French cheeses or raw meats that often accompany a Christmas meal. They can contain bacteria that can cause birth defects in fetuses. For more info read what not to eat during pregnancy.