Being the after thought friend

I’m 21 and in my senior year of college. Since freshman year I’ve been losing friends left and right. My ex best friend was the first to go. Next was my roommate and any friends that were apart of the group drifted apart while a few stayed together. I ended up by myself. All of my friends from home and high school are my true friends but we don’t go to the same college. I’ve made 2 new friends over the last year but I can’t help but feel like an after thought to one. One of them has moved back home so I’m really by myself again. I realized it tonight when I basically invited myself out with the other friend I’ve gotten close to. She was already at the function with her group of friends. She didnt even tell me that they made it. She’s gone out multiple times this semester alone. Not even bothering to invite me. I’m not gonna lie it hurts. After losing friends and always being the friend to make sure every else was good being the designated driver and all. I just don’t feel I get the same love back. I’m either inviting myself to things or inviting others. No one cares to include me it feels like. At this point, I’m over it. I’m over trying to get my party years back and have fun. I’m over being the nice, chill, easy going friend and still not be the first thought of someone to go out with. I know I may be the problem somehow. I went through a long period of isolation and it was the worst thing, but maybe I’m just not meant for anything but to finish school and get my degree. Maybe trips and vacations are my next thing but having friends to hang out with socially on the weekends just doesn’t seem like a real thing to me anymore. I’m honestly sad and just need some words of encouragement or advice🥹