How to manage friendship breakups?

I'm going through what feels like an influx of issues with a friendship group from home I've known since I was a child. The final tipping point has come today after being told I'm not invited to one of the girl's upcoming hens, I've realised these people just do not value me the way i do them.

I'd like to take space from the whole group, probably forever, but am left with so many mixed up feelings. I'm so hurt and sad, kind of ashamed (like loosing this friendship group says something about my ability to hold on to friends - I've know these women 20+ years, since school). My brain knows that this is an invitation to find friendships more closely aligned with my current life, but I just want to cry!

Any advice for dealing with changing friendship dynamics with grace? Please be kind, I am feeling very sore.