Ok, so I have no idea who should I take advice from so imma just tell you guys the whole story and let see how this goes.
Ahem soooo, basically my best friend from last year who I trusted start hating on my other friend who I also trust sm. She called her toxic, and the school pet and manipulating all that but when I asked her, she said she didn't do anything like that and was very hurt... Then my best friend start going around making ppl hate that girl, and I was the only defended her, everyone else stood on my best friend's side and start accusing my friend of all kind of stuff.
And when she couldn't take it anymore, she swears at them and all that stuff but then they flipped the table upon her and start being innocent "She swore at us omggg" and all that making the whole situation worse. And once I had my guard down, they succeed making me on their side since she was my best friend and all. Then when that girl found out I decided to be on their side, she got really pissed and starts sending all the stuff I said about them to them, but since I defended her the whole time, she couldn't send it and delete it all. From there on, I ignored that girl, but now my best friend are secretly backtalking me and making everyone distance themselves from me. IDK WHAT TO DO ANYMORE
I tried talking to that girl too but things seem to doesn't work out as before, and my others friend starts acting awkward around me, and my best friend completely ignores me unless I start the convo first.
PLZ TELL ME WHAT SHOULD I DO?! AND WHO IS RIGHT OR WRONG HERE?!

I'm sorry about what happened OP. Your story is kinda relatable because I shared a similar experience when I was in 4th grade.

My best friend hated my other friend and everyday trying to make them like each other or at least be peaceful around me was a torture. It put a toll on me. I couldn't focus on anything nor my studies. It took me two years to know how both of them were leeching off of me and only stayed with me because they wanted to take advantage of me. To this day, I'm still glad I got rid of both of them.

Honestly speaking, your best friend is the only one wrong here. It's like a chain. Your best friend started the mess, involved other people into this mess and they joined in to attack your other friend. Then she goes out of her way to shit-talk about you behind your back.

If I had to advice, I'd say first you try to ask your best friend why is she doing that. Confront her. Be rational. You might feel it's risking your friendship but no, it's a test for her. If she was your ''best friend'', she'd be honest with you if you are persistent enough. If she was just a hypocrite, you can break your friendship then and there. Such toxic people will never let you rest peacefully. I myself was a victim of such a case.

As for your other friends, it's just a rumor they heard. If they are your friends, they would stick with you and not believe some stupid shit your best friend has spread. It would be awkward at first, but you have to be bold and make them believe in you again. If they're just some hypocrites, don't bother even talking to them. You have your own self respect and worth. Don't waste it on some side characters in your life who would ditch you for some rumors.

As for the other girl, I suggest you talk it out with her. She was the victim of this whole mess that started so it might have mentally disturbed her a lot and she might need a helping hand. Don't worry if things don't work out as before. She just needs some time.

In short, try talking to everyone close to you who was involved in this mess and try to fix things. They'll forget about this eventually and ya'll will be back to normal but if they're not who you thought them to be, don't associate yourself with such toxic people. After all, you've had it hard too. Always remember, friends come and go. It's up to you to choose the right one. People like you will eventually stick with you.

I wish you all the best. If you have any more problem regarding this, feel free to say it here. I will try my best to help.