I've had some brief (thankfully) periods of anxiety. Thought I'd add my experience to the pool here for completeness.
Most of your description feels familiar but there were some interesting nuances.
There were certainly situations, especially involving other people, that would trigger rather strong anxiety attacks. Sudden tunnelvision and extremely strong urge to get out of the situation. At the time I had no clue whatsoever why I would suddenly have this reactions. Years later reflecting on it I have realised it was probably only because the people, or situations, simply worked as reminders of things that I was subconsciously scared of. I imagine PTSD sufferers experience something similar when specific sounds, or smells, can be a trigger.
But there were also other attacks that were much, much worse. These times I was completely overwhelmed. My sense of self and reality would be gone, I was convinced that that the only thing keeping reality together at all was my mind, and if I didn't hold on and fight back I would reach a point were it all would simply dissolve, or lose cohesion somehow. I could do nothing at all but lie in my bed and try to hold on. Any sensory experience at all was unbearable, sound, sight, touch, I just desperately needed everything cut of to avoid overload.
I remember how my (now) wife would try to comfort me, gently stroking my hair as I was lying there curled up on the bed and even that simple sensation was too much for me to handle. How utterly helpless she must have felt.
In any case, this lasted for a few weeks as I recall it, and basically stopped entirely once was I was ready to seek help and learned that there is such as thing as panic attack. I guess just knowing it was a thing was enough to break a negative feedback loop.
Years later reflecting on it I'm thinking that the main contributor to these episodes was simply growing pains. I was twenty something at the time, probably going through both physiological, as well as psychological changes and things were just unstable during the transition. I think the periods also correlates with jumps in belief systems.
While I've always been "open minded" and kind of accepted both atheistic as well as christian beliefs as plausible, I was busy making room for both buddhistic and some decidedly occult narratives. I guess foundational refactoring like that would cause some temporary distress.
In summary, I guess I just wanted to say few things.
For those lacking the experience of true panic attack: It can be pretty bad, way beyond a state where "do the thing you are so scared of doing" even makes sense to talk about.
For those suffering from it now: Perhaps it helps to know that it's not just you, and one day it might be just an enriching experience you went through
And for those trying to treat it: Perhaps CBT is not the right tool to approach it in all cases, if the underlying issue really is subconscious conflicts there may be other ways to help with resolving/integrating them.