Good advice from Echoes. Do you take any meds? (can help)
I had this problem---still do sometimes---but I have found it doesn't really matter where I am living...although, when I am 'triggered' and the switch is ON, crowds are very difficult...especially inside a place (movie theatre, store, restaurant...)-------or waiting to go in. It used to be a constant, but over the years, it has changed to just happen at times that (for whatever reason, I don't always know) that switch goes ON, and I am fearful, overwhelmed, and really need to get out of places that don't 'normally' bother me at all. That is how you learn it Is internal---when you have times that it does not happen. The more (I found) you avoid the places, the stronger the fear---I actually didn't use any meds till I was in my mid 30's, and the problems began in my late teens...there were even places I worked that had me in that awful place all day (I blamed it on the florescent lights...and some days I left work early...) ...sorry for the ramble,
I am remembering...
I now find cities nice because I feel anonymous, unnoticed (though sometimes the thought of going into a city will cause me to fear the fear, once there I am OK...)