This is really relatable. I've been agoraphobic since childhood as well. I prefer my "safe space" at home. It isn't uncommon for me to have gone months without going outside (strange because I actually love being in the outdoors)--for fear of being seen by others or having to interact with others.
Grocery stores and public places send me into fight-or-flight (after complete overload), and my partner has often had to help guide me back to the car (everything turns surreal, and it isn't uncommon for me to lose my bearings entirely).
I also have trouble with wide open spaces (open sky, scenic vistas, etc). I have no idea why, but I physically feel like my body is going to float into the sky when I view open spaces. Just as an example, my partner and I went to watch a solar eclipse at a quiet park. I had to wrap myself around / cling to my partner due to this "fly away" sensation. (Maybe it is similar to a vertigo sensation?)
Oh, gosh, I know how it feels to not be able to walk or do anything, let alone think straight during
those panic attacks.
The definition of Agoraphobia is fear of open places and I think some people do feel strange outside
in large open places.
I don't get that, but, I do have an odd sensory issue that just happens and I don't know why in
totally dark places. Ever been in a cave and the lights go out? Or a dark tunnel?
It's sort of like that float away sensation for me. I feel like I don't have a body and no perception
of self. If I shut my eyes, it helps, but not completely.
I must have dim night lights on to sleep.
And strobe lights freeze me. I can't move.
The sensation you are describing isn't like vertigo though.
I have meniere's disease and I get vertigo that lasts for several days.
It is the sensation you are spinning on a very fast merry-go-round and you can't focus
your eyes as everything looks like it is spinning very fast around you also.
I can't do anything but stay in bed when I get those days. Going to the bathroom is a horror.