Struggling with C-PTSD in My Relationship

I have C-PTSD and it’s been activated since the beginning of the year. I can’t go more than a few days without breaking down. I feel like I can’t tell the difference anymore between true threats and my brain misfiring. My biggest problem is I can’t determine if I’m overreacting to the way my boyfriend talks to me/treats me or if it’s really as bad as it feels. I’ve been married. I know what “rough patches” feel like. I don’t want to give up on our relationship but he’s making me feel worthless. Or I’m making me feel worthless and blaming him. How do I know?!