What should I do?

I loved the idea of being in a sorority but it isn’t at all like I thought. I thought we’d just all become close after a few months but it didn’t happen. Even after being in a whole year I’m still not feeling the sisterhood. My pc is cliquey so it’s hit or miss if I get invited to things. Like getting to an event and finding out most of my pc went to eat before they got there. It’s hurtful because these are my sisters. I invite them to things and a lot go but I always initiate. I feel so disappointed because I was really looking forward to being close with these girls. I’m not sure if I should stay or if I should give up. What would you do?