Is AUTHOR wrong in the post ? POST : So i've kinda been thinking this through and i just feel somewhat annoyed/angry over the fact for this happening.  
Earlier tonight I talked to one of my friends after she told me she had a pretty bad week, of course I wanted to know why, and it was quite odd for me as I quickly picked up, that there was a bunch of background noise. She told me that she'd rather talk about this face to face, which im absolutely fine with, and afterwards said that she just wanted to celebrate our mutual friends birthday. Let's call this friend of ours Alice.  
So Alice told me from pretty much when she turned 17 that i had to come to her birthday and it would mean a lot for her if i came, and as im really not a social person, the type of guy that'd rather just have a beer and stick around at home with my dog, i still accepted the fact that she really wanted me to come. I've spoken to her about this multiple times throughout this year, and i kept saying that i'd of course come as she wanted me to.  
After realizing that i didn't even get invited to her birthday party (which is tonight) i feel quite odd about this, of course i know when her actual birthday is but i never knew when this party would take place.  
The point where i feel like im in a dilemma is that i've set all other plans aside for new years to be together with this group of friends, including her, but now i honestly don't feel like going   
I don't know if im just acting like a twat and taking things too personal or if i've done something wrong (not that i know of) but this kinda puts me at the point where i'd rather just stay at home for new years  


TL;DR After talking to a long time friend about her birthday for a year ish, about me coming i didn't get invited, which leaves me confused about what to do for new years.