Being ‘unfriended’

I’m really shaken, I don’t quite know how to react or what to do from here.
I just moved back to my hometown after 6 years of living away. I was looking forward to having the support of my family after having a baby, and also spending more time with my small group of girlfriends I’ve had since school 11 years ago.
Naturally over time, I haven’t been as close to them, life gets in the way and u catch up less and less often. But I’ve always considered them my close friends - to be honest, they’re my only friends. I always look forward to speaking with them and finding out how their lives are going. I genuinely care for them and we could talk about anything and everything for hours on end.
Recently, I’ve noticed that there hasn’t really been much communication. When I told them I was moving back to the area, no one even commented. I tried to arrange a coffee date whenever they are free next - I’m always available these days as I’m on mat leave, so am super flexible. When no one even bothered to reply, I got the feeling something was going on. I sent a message to one of them so let them know I was all moved in, and after having some hard months with PND, I was looking forwards to reconnecting with her.
No reply.
This was a week ago. Tonight I finally get a reply. And it’s pages and pages long. And it was a hard slap in the face. She detailed how her and the other girls all thought i was rude, unappreciative, and selfish. She ended it with saying she has no interest in continuing trying to be my friend.
This came as a total shock to me. I had no idea any of them felt this way about me. She went on to give a number of examples of my ‘unacceptable behaviour’, and to be completely honest, I had to ask her if she was speaking to the right person, because nothing she said actually happened! An example - on my hens night 2 years ago, all I did was complain about how badly organised it was and how I wished I was somewhere else - I absolutely never said anything like that! I don’t know where’s this is coming from. But I’m crying just thinking about them all discussing this behind my back, and yet say absolutely nothing to me. Like if they just ignored me I’d eventually just disappear out of their lives.
I just don’t know how to go forward. I already have low self-esteem and am very self-conscious. Im not perfect, and I admit I do get caught up in my own life at times and can go a while without communicating with them. But I know they all have busy lives, and I consider myself a very low-maitenence friend. I guess I’m just in shock, and feeling very vulnerable. I just needed to share.