dreading being alone at christmas

Every year for over 20 years i used to go to my brothers for christmas where all the fanily were,even when they got divorced about about 4 years ago i was still very welcome ,it was a great day and was very merry and i felt loved and somebody.I fell out with my sister in law last year as she stopped getting me anything for my birthday(even a card) when i bought for her and all her family including new partner,she missed my birthday for 2 years and i contacted her as i was very hurt and told her just to forget it,there was a big argument as her partner turned agressive towards me,i never spoke to then for a year,i cant beleive she did this and i feel rejected after all i did for them,her new partner never liked me ,with me being the brother of her ex,and i think she stopped buying for me to provoke a reaction,i am hurt that she went along with this as she was like a sister to me.I was home alone last year but my nephew and neice came over to see me for an hour,and it looks like im home alone this year again.No one invited me and i dont know why ,i am a good laugh at christmas and conduct myself properly.Its crap when someone asks what im doing at christmas,if i was a bad person i could understand but im not ,im a good person,one of my work mates asked  me to go out for dinner with alot of them......not sure what to do might feel uncomfortable as i dont know alot of them.