Getting over friendship disappointment

Hey everyone – for some brief (as much as I can) background – I had a falling out with a friend about 4 years ago because I was in the house share with her and some other girls. One of the girls took a massive dislike to me for no apparent reason and started a 9-month long tormenting spree (eg would throw out my food, make up stories about me, leave me out of plans) to the point where I had to move out, quit my job in the city and move back in with my parents at the age of 28 because I had nowhere else to go – I was a completely broken person.

(And yes, I’ve also considered the possibility that I’m the problem but I’ve never had friendship issues to date – I’m a real people pleaser and generally get on with whoever I meet.)

But this individual wasn’t actually the main problem- it was my “best friend” that stood back and watched it all happen. She even decided to just go to the gym when I was packing up all my stuff & didn’t hang around to say goodbye.

For the sake of my friendship group back in my home town, I somewhat kept in touch with her and see her now only with my other friends. I always get the sense that she’s told the other girls another version of events & whenever I’ve tried to open up to the others about my “trauma” of the situation, it gets shut down and they say they don’t want to be involved. I’ve been left feeling let down by all of my friends in this situation. I’m a fiercely loyal person (sometimes to my detriment) and if I was one of the other girls, I would’ve held my “friend” accountable in a non-confrontational way so I just couldn’t understand why I was sudden being treated like the villain.

Fast forward 4 years & they’re still in my life and it’s still bothering me. I dread spending time with all of them and get a horrible anxious feeling that they all think I’m the outcast of the group. I’m also self aware enough to know that a lot of my thoughts & feelings are part of the problem & I may be building it up more in my head. I need to get better at realising everyone is the main character of their own life & chances are, the girls did simply just want to stay out of it to keep the peace. I know a lot of people will say just walk away from all of them, but they’re all I know in my home town & truly don’t want to be left with no one, and they do bring joy to my life in other ways.

So…. I’m on the hunt for a self help book that actually “helps”. I’m not quite sure what I’m looking for but based on the above, was hoping someone on here could suggest something. Thank you so much in advance!