My best friend became the person I dispose the most, and it broke me

My best friend turned into the person I hate the most. She was the person I told everything to, the person I trusted the most, one of my favorite humans to exist. Then she broke my heart. (In a non romantic way). She started treating me like shit, and I just won’t go into the details cause it has been almost 2 years now since most of it all went down and I thought I was over it all until today. I realized I have no idea what’s going on in her life or how college is going, or anything. We’re not even friends on Facebook anymore so I can’t stalk her. I still get so emotional just thinking about it. I can’t even pick a certain point where it all started going wrong. It just fell apart and I miss her so much and hate her at the same time. I never thought it would be this way. She broke me. Today I don’t open up to people as much, honestly I don’t really have any friends and I think a big part of that is because of her. Half of me wants to reach out and just see how things are going for her but then I know this would not be a healthy thing for me to do. I think a lot of what brought of up these emotions again is my best friend today (we met right before my ex best friend and I stopped being friends) is kinda treating me like shit the past few months and I just keep telling myself it’s because she is going through all of the senior stresses and getting ready to graduate high school (she’s a year younger then me) and the stress of college and all that but I think deep down I know this isn’t the case. I didn’t treat her like shit when I went through all of that. Ugh why do I suck at picking friends?? Literally every friend I’ve ever had has ended up treating me like shit or we just drift (and that’s okay, it’s life). Well if you got this far thanks for reading my rant. There’s really no point to it I just had to get it off of my chest and since I can’t tell this to my current best friend cause she’ll just get pissed at me for accusing her of being shitty to me and it will start an argument. Thanks y’all!