My friends treat me like crap but I don’t want to lose them. advice?

So i’ve been in this friendgroup for almost a year now. I transferred to a new college going into my sophomore year and was having a hard time meeting solid people for the first month and a half of school. Then I met these 4 girls and everything started to look up. I was invited places, I had people texting me asking what I was doing, and i felt like I was finally connecting with people. But in the back of my mind i felt like they were using me. They asked me on a trip so I would drive my car. I tended to bring alcohol to our pregames or order ubers (i’m a very generous person with people i care about, which most people often take for granted.) I was always there for them when they were struggling and i made sure to not really talk about stuff i was dealing with. I kinda knew a few months into being friends that it wouldn’t last because i always felt anxious and worried around them and we have different morals/ambitions. I’m not a huge partier, and i felt like everytime we hung out at least two people were really drunk. I have some good friends who go to different schools, and over this summer I really re-evaluated what i wanted out of my friendships. A week ago, I was having a bad day and my mood rubbed off on my friends. I didn’t say anything to anyone, but they started ignoring me, even turning their backs when i tried to talk to them. When i found out why they were upset, i immediately apologized individually. They still ignored me, and now i feel like im back to square one. I know that this logically is not a beneficial friendship for me, but we already have plans later on this year that i’ve already paid for and i can’t get that money back. I don’t know what to do, but this week has been really hard on my mental state.