Friends end when high school does

So for the past few months I've been struggling with losing my childhood best friend along with almost all of my friends. I went from having many friends to only one true friend aside from my long distance bestie. I'm graduating in a few months and I'd be lying if I said there wasn't a part of me that didn't miss my childhood bff. We stopped being friends due to her getting mad at me for hangin out with this girl she and her ex didn't like (this girl being the only one to stick with me through my issues last year when everyone else also stopped talking to me then, although I remained friends with all of them we just had some distance). When two guys saw me and my friend hanging out, they told my ex bestie and she sent me at least 10 paragraphs yelling and berating me. To try to calm things down, I decided to not respond (which I thought was the right thing to do in the moment.) After several months of her and her ex and their large friend group laughed at me in the hallway and threatened me, I decided to reach out and apologize to her. Things were still paused and it wasn't until this past thanksgiving where we finally made up and things were going well until she told her ex ( and yes they were broken up after 2 months of dating but still remained friends) about us talking again that she just stopped talking to me. Now she sometimes waves to me or just straight up ignores me and I feel really lonely. I miss my best friend and the worst part is that she doesn't even think she did anything wrong.