Dealing with Trauma and Abandonment Issues in a Relationship

I had a traumatic event happen to me unintentionally because of my ex partner, and I broke things off out of fear of being unsafe. It turns out I was having a 3 week emotional flashback to the last times I was unsafe, which felt like an unending, exhausting mania session that really disregulated me. I've been trying to remain friends and work on my triggers and unlearn my attachment style, and try to work towards building our dynamic up. They are very good at compartmentalizing and I am not. I'm still being triggered by my percieved rejection even though I rejected the relationship because I was scared of being hurt. Now they are distant and that makes my abandonment issues flare up even worse. I have a hard time interacting with them without being triggered in one way or another. It's like a roller coaster, I find myself crying over my own hyperawareness and assuming they've moved on. I lost a lot of friends last year over them betraying me and I'm so scared I'll be hurt and abandoned again. I would appreciate kind thoughts, suggestions, camaraderie.