i really miss my best friend

she's not gone or dead or not my friend anymore, we're just distant. I miss all the times we'd go out after school and have fun and talk, I'm partially to blame for it. I stopped asking mainly because I wanted to study more and do more homework and also play my piano,but I've also stopped asking because most of the times I'd ask she'd either say no "I can't be asked I have so much to do" (so much as in sitting at home doing nothing texting her online boyfriend), or she'd cancel last minute after I've been so excited for like the past week. it has only been a couple of times we'd ACTUALLY hang out if it's not after school, probably like 4,5 times in the past two years. we used to hang out every day after school but when it was like June she just stopped. I miss her. I didn't think abt it much since we'd talk in school every day but we're in a trio. I've always felt left out, but I've managed to tolerate it most of the time, recently tho she and our other friend made fun of me, the vibes have been off. there was a situation where our friend's friend was talking about me and my other friends during a practical in science, she didn't speak up and defended me behind my back tho. I told my bsf this and she just said to leave it alone since this is the first time it's happened in a while. but it should have never happened, why have there been situations where our friend has spoken about not only me but also about my best friend behind our backs. I love them both so much but I'm tired of going back to those times. it still hurts because I STILL feel like the odd one out. I just want to go back to when I was fine and could tolerate feeling left out, and also not having to talk abt each other's flaws and trying to fix our friendships. it honestly feels like everything's crashing down and I can't do anything to stop it. I don't want to stop being their friends. my heart feels like it's dropping more and more every day thinking about us. I miss my best friend so much