I can relate to associating holidays with traumatic events. My TBI happened the Monday after Thanksgiving, and I was still in the hospital over Christmas. This causes feelings of guilt, as in my mind it was my fault that the family missed being together for Christmas. Along with that come the accompanying depressed feelings.
Here are some things that have been helpful for me.
I celebrate the fact that I survived and have the chance to spend this time with loved ones.
Try to disassociate the trauma with the date. If the weather is good go for an outing. Do some activity together that is in a different setting and provides some enjoyable outlet.
For me time is a healer. We have celebrated two holiday seasons since the year of the accident. 2012 was easier than 2011. I expect 2013 to be better yet.
Best to you.