Need advice please on ex high school friend

Me 28F. I graduated high school in 2013. The ten year high school reunion is coming up (I’m def not going)

One of my friends who I still keep in touch with messaged me and a couple of friends who I used to speak to in high school in college and asked us all if we’re going. I messaged her privately and said I’m not going.

One of the girls in this group …. Used to hang out with a girl who didn’t like me and was a bitch in high school. In college we got over it. But I still think she’s a snake.

I readded her now , which I regret. And I messaged her asking if we’re still cool. Which now I realized I shouldn’t have done. I think this is one of those friends I have to let go of.

I’ve lost touch with couple of high school friends and now it’s awkward when this other high school friend comes and invites us all together. And this high school friend of mine doesn’t seem to understand sometimes why it’s awkward for me…. Like it just goes over her head.

I feel kinda sad because I’m losing friends and I’ve lost a lot along the way.

Now I’m feeling annoyed because this girl is bringing people together that I’m not too comfortable being around.

Idk how to tell myself it’s ok to lose friends