Need to vent this out - My friend betrayed me

Problem/Goal: Bumabalik anxiety ko, I'm not even diagnosed but the feeling is not normal for me - nanginginig kamay ko, mabigat pakiramdam and all

Context: I have a long time friend na may secret animosity towards me. I kept this to myself kasi feeling ko nung una nag-overthink lang ako. Pag may nagpipraise sakin, she tends to squeeze in with her side sarcastic comments. One time, my long time partner (wlw) and I went on a date and we decided na isama siya as she's waiting for her partner din, while looking at us, she suddenly asked if boring ba daw ako kasama sabay tawa. I felt so offended pero sa loob2 ko baka nag overthink na naman ako. Maybe she was just joking. And when my ex and I broke up, she was consistently chatting with my ex. I knew my ex well and I know that it was just a friendly chat cos she's also like that to my other friends. Pero this specific friend was checking on my ex while she suddenly stopped communicating with me. My ex told me na it came to a point na yung friend ko was flirting na. I told our other friends about it pero tinawanan lang nila. And now she's back in our hometown and wants to hang out with us like nothing happened.

Masyado ba akong seryoso? Diko ba gets yung humor niya? Bat parang ako yung guilty? My hands were shaking upon hearing her name. This is so petty pero I don't get na parang wala lang sa kanya while she's clearly crossing the line. Deep inside, I want our friends to cut her off or hate her for doing it but they don't seem to see her that way.