I'm so worried and hungover from last night's works Xmas party 
Basically, since I started back in September, there is a girl who took an instant disliking to me from day one, very loud, likes to be seen and heard type of girl. Few snidy comments were made and she would gather the team together to chat but not include me. Long story short, I messaged her a few weeks ago asking if we needed to talk as I didn't understand her hostility towards me. We did and she said when I started, I 'ruffled some feathers' as I had been in a higher position before this one and was a but frustrated at how quiet the workload was compared to my previous job.
Anyway, things were fine, though she was still dis-cluding me from conversations, lunch breaks together etc.
Last night's Xmas party, she was very close to one of the girls who works downstairs - I have never had any dealings with this other girl nor even had a conversation. I tried to make conversation with her & she just looked at me rudely. I asked her why, and she said "no-one likes you" ! This obviously pissed me off so I kept asking what she meant when she doesn't even know me!
Outside the bar, she randomly called me a 'slag' which tipped me right over the edge (as I was raped 4 wks ago) so I retorted by calling her fat-ass, which I know I shouldn't have, I was just so angry 
Now I'm so worried I will lose my job over this as they're like a big clique and I have all these crazy feelings that they may go collectively to my manager and/or HR and say something like I'm not being part of the team or something, and also my comment to her last night? 

But what gives somebody the right to call you a slag and tell me no-one likes me, when I've never even had an exchange with this girl and was being nice by trying to make friendly conversation with her ??? 

My anxiety is through the roof right now 