Wow so many replies in a short space of time - I am so sorry to you all! It's a really lousy thing to go through.
My 'breakup' is embarrassing really. Given that we are all grown women. I challenged the matriarch of the group as she had a go at me out of nowhere over something really trivial. She had been really nasty and I quite rightly told her that I wasn't ok with how she treated me. She doesn't like being challenged as she is a bit of a Narc so she started excluding me gradually and the rest just followed her like sheep. I should have walked way then - so wish I had - but we had such a long history and our lives a bit intertwined. I am godmother to one of their little girls, our husbands are good friends, we live close to each other and all that. There was a toxic one in the group also and I am pretty sure she stirred things up in the early days but can't prove it.
I kept on trying and would meet up with the others seperately at first because I thought F it - why should the matriarch isolate me from my own friends. But it became one-sided after a while, with me making all the effort. They stopped replying to texts and barely congratulated me when I had DC2. I was still in a group chat with all of them for quite some time, hoping things would go back to normal but then realized there was second group chat going on with just me excluded. That hurt so bloody much.
During lockdown I left the group chat and messaged the Matriarch and explained I felt hurt and rejected and that I was moving on. Haven't heard from any of them since.
There was one that I was particularly close to. She stuck around for a while but it became awkward as I was so hurt and it started to consume me a bit. I vented to her a few times and had expected her to step in and try help smooth things over but she didn't want to be involved any drama. So I guess I pushed her away although I tried not to go on about it too much. She then had alot going on in her own personal life and we completely drifted. I miss her so godamn much. It's her that I am 'grieving'. The others I can live without and realize now that they are not true friends or even decent people.
I have 3 other good friends who are great but they don't live locally so only see them maybe once a year. And this whole thing has really affected my confidence. The rejection has made me feel like I wasn't a likeable person. I was scared to meet up with my other friends and even wary of meeting up with my SIL's who I am close to.
It's crazy because before all of this I was always so confident and easy going. I always had lots of friends in my 20's and made friends really easily.
But I think i'll get there eventually... A work colleagued asked to meet for lunch recently and I cried! I was so happy and relieved that someone actually wanted to see me again. It felt so good having plans with a gal pal like that again.
No more social media for me. As someone said 'out of sight out of mind' - It's the only way.
Thank you all for 'listening' and for your replies. For those still struggling...I came across the below online and it helps me on the days I feel sad about it all - hope it helps you too 
20 Things to Remember When Rejection Hurts