Drink more egg nog!!!
The thing I did when I felt that way was busy myself with something. Listen to music with headphones.
If they haven't taken the time to know you that's their loss
When I have felt that way, I have found a book and a quiet corner. Or even taken a nap. Or maybe started a side conversation with someone and just sat and watched. I don't have your issues, so I don't know if this helps, but it's usually pretty easy to slip away during certain times. Often enough, you won't be the only one who isn't feeling completely sociable. One more thing to remember...if no one wanted you there, then you would have been told that and "uninvited". And you can't know how everyone thinks of you...so don't assume too much. Odds are that you aren't as prominent a figure as you may feel you are, and your presence there is not at the forefront of everyone's thoughts. Everyone will be hobnobbing or gossiping or whatever..with everyone else. Just try not to stick out like a sore thumb and smile when someone speaks to you. You don't have to "play ball", but you can be decent company. You can get through it.
You know, you could just put your question in the details section. You get 700 characters of writing.