Putting this here instead of r/relationship-advice because I'm pretty sure the problem is with my brain, not my relationship.

To give some context, my boyfriend doesn't handle stress the best; he tends to either shut down or talk trash about himself. Everything bad that happens with him is automatically his fault in his mind, even stuff that's just plain bad luck. We've had talks before about how I can help break him out of that cycle, like smothering him with affection or offering to let him tickle me. He's getting better at handling these things with therapy, medicine, and time.

Yet I still find myself instantly super anxious whenever it even looks like his mood's about to tank, and I need to find a way to minimize that response if I'm going to be helpful to him when he has these moments. Otherwise I freeze up and just watch him as he does whatever he's doing, which only agitates him (understandably).

His mood went south yesterday and again today, and both times I think I was nervous because you never really know how long these moods will last for with him. I've seen them keep him down for days before, and it's agony to go through that with him because unless we're physically together (which we rarely are since we're semi-long-distance) I can't do much for him. Talking it out is hit or miss since he makes points I struggle to refute, so trying to help him from a distance just feels like a high-stakes debate that I'm always losing. I feel like a failure because I can't help him.

And now he's in a mood again, and I feel so unsteady and unsure. How do I calm down enough to help him? Why do I even get so, *SO* scared when he's like this, when he's never hurt me or even yelled at me? Yes, I have past trauma of having to be hypervigilant and meek when someone would get upset to stay safe, but he's never done anything to me and it's been years since I've been around the person those traumas are linked to.

TL;DR: I freeze up/panic when my boyfriend is in a bad mood, despite him never harming me in any way. Why??