Buggirl you are doing this for you and you are worth doing this for. Last year was my first sober Christmas in a long time, I went to nothing that could be described as a booze up although I did go to some gatherings that had a different focus. I sailed through the Christmas period feeling great and staying sober.
Nobody's job description says they have to attend an annual booze up. If necessary show your face while you have a soft drink, then slip away - nobody will be the wiser. If not necessary then don't go, stay home and do something for you or go to the movies with a friend.