Feeling really bad

I had a friend group last year. They were people I really liked. But this year I wasn't in the same class as them. I struggled to keep contact with them and because I felt we were drifting apart I didn't make enough effort to make me included. I them tried to invite myself once but got lied to saying there were too much people at the party because they didn't want the friend(not from the group) who was coming with me. We continued to drift apart and when I made the decision to make efforts again i learned that a girl in the group said things about me behind my back, and didn't want to come to hang outs if I were invited. Made me drift away even more because apparently she wasn't the only gossiping( it wasn't really mean things either) I talked to her about it but she try to make me the villain saying that she thought I wanted to hit her because of a ***, but it was posted after I learned what she was doing lol so she was lying. She didn't think she was excluding me. At this point I almost never saw my friends at school let alone outside of school. I invite them all to my birthday but they even make the effort to respond for the gift or to know if they were coming. My friends organising my birthday had to run after them. For the last hang out she did it again. I talked to my closest friend in the group, she first told me that they thought about it but some in the group said that they wouldnt come if i came. She then told me to get over it, (not in a mean way), that it was a long time since ive been with them, a lot from the group didnt even thought to invite me and she couldnt do anything about it because i dont talk to the other anymore. (Dont really agree with that i talk with at leat 5 person of the group and i invited them to my birthday but i see why she says that.)She also told me that I was progressively excluded from the hang outs. Now I'm not part of the group and it hurt me very much. I feel like I list meaningful connections and I like that group very much. I feel like if I did more efforts back then instead of waiting to be seen and invited it would be different. But at the same time I feel like I did some efforts (my birthday for exemple) and I absolutely hate running after people. But maybe my efforts were too late.

I also don't know if I'm crazy to think that the girl is really in cause of most of my drifting apart, she don't think she has anything to be sorry for, even though she participated in my exclusion and she hadn't any reason to say such things again