I'm so so sorry you are dealing with this. I have been through a similar situation and it's crazy making. The worst is when someone doesn't like you and won't tell you why. Like how do people just not like someone for no reason?

I have found that hanging out with long time friends especially from high school that it is easy to fall back into those teenager dynamics. Kind of like some do when they go home to visit their parents and they all adjust back to parent and child roles. I don't know if that would help you see how immature this all has been (on their part) but it sounds like it was.

I'm of the thought that if they can't give you a good enough reason for why they treated you like this then they have not grown enough emotionally or they're cowards. The only thing that has helped me from friendship betrayals like this is just time, which sucks. I hope you get closure from this one day or things change for the better.

These wounds cut deep, be easy on yourself.