Unable to speak?

Hello, apologies if this isn't the right forum but I googled quite a bit and couldn't find an exact relation or anything of the likes, however something did point to anxiety, I don't really know if it fits or not.

Basically sometimes in high stress situations I am unable to talk. I don't know what to say, somehow feel as if I don't WANT to say anything and at the same time not being able to. I try to find the right words and/or thoughts to speak but I can't and I'm trying to understand why. Is this some sort of anxiety at all?

It happened again just now because I had an appointment scheduled at a mental health clinic and my caretaker would take me to it. For clarification, since I'm not a native english speaker so maybe my choice of words may be wrong, I am not physically disabled, I live in an assisted living community (I hope this is the right term for it).

I remember it happening in my childhood quite a bit when my father would yell at me and I would just sit there and not say anything, maybe to defy him in a way, I am not quite sure.

Anyways, I am not sure where to put this... behaviour(?) of mine and I have quite a bit of trouble speaking my thoughts, writing them down seems so much easier.

Thanks in advance.