Struggling with avoidance/self-isolation

I’m almost 19 and for as long as i can remember i’ve struggled with keeping and maintaining friendships. In a handful of my previously ended friendships, my boundaries weren’t respected, been intentionally excluded from hangouts, been insulted, etc. these events have only exacerbated my self-isolation habits. In addition, I’m also in a relationship with (18M) and i really struggle with both trusting him, and feeling regulated in our relationship. I don’t have any accessibility to a therapist either. I’m so tired. I know that my behavior worries people in my life, but I only ever feel comfortable or ‘safe’ when I self-isolate. If any of you have also struggled with what I’m struggling with currently; please tell me how you cope/d, or if you have any advice that’d be awesome too.

tldr: i’m depressed, i struggle with self-isolation and keeping friends. what’s your advice?