Work Problems

There are a group of girls at work who are all very 'close'... Their whole friendship seems to be based on bitching about other people, I just don't have time for it! 
So sometimes I feel that that maybe I'm a bit standoffish because I don't join in on slagging people off??
They internationally exclude me from all their plans.
To be honest, I haven't minded the last year and a half too much, I'd rather just get on with my work... Yes, I am a geek.
But I can feel it starting to get to me. I feel pure shit about going into work, because I know it's going to be whispers and sly looks.
It makes me feel weak that I'm letting a group of girls make me want to leave a job I've worked hard to get. But I do, it feels like a toxic environment that I dread going to and rejoice the second it hits 5pm.
The money doesn't feel worth it at all at the moment.
They're all heading out tonight for halloeeen fun and I was sat directly next to them whilst planning. 
I know girls are known for bitchiness so I'm starting to think I was meant to be a boy!!
Dreading Monday already 😭