The stuff I'm recommending is what you can do when you're away from the situation, so that it doesn't have the same effect next time it happens. It's usually subtle, and may take doing but several times, then the situation comes up again and you find you're responding differently.
If it's automatic, then you don't have power. These methods will help you reclaim your power.
I think right now you're unconsciously clinging to something that rejects other ways of dealing. So maybe deal with that first. Perhaps you have an old message that tells you you're not in control of it, and at the time, that message served you, maybe saved you. But you're grown now, so whatever is stuck in the old situation needs to get caught up with how much you've grown, how capable you are.
You don't have to answer this except to yourself, and even then only if you choose to, but how old are you when you react to this trigger?
Don't be surprised if other shit comes up. I recommend you don't judge or resist it, but be the kind of person you needed, maybe supportive, understanding, accepting, and capable, etc. Sometimes when I deal with the shit my mom did, I step in and am there for myself in the ways I needed. Like when I saw something traumatic and she negated me, I step in and give myself the support I needed, because I'm capable of that as an adult and she wasn't.
