Shopphobia is a problem for me too.
Of course I desperately don't want to be in the shop to start with.
I need to see my escape route, any form of obstical in my way of the door to freedom and a form of panic starts to set in.
There was briefly a woolies where Asda down by the beach is now.
They set their aisles out so that you couldn't get out without zig zagging, I couldn't get out quickly enough.
Only ever went in once.
I was once, and believe me only once, persuaded to join Mrs Donsdaft in a visit to Ikea ( it was her birthday or I'd never have said yes)
I was in just under 5 minutes, I couldn't get out, I nearly went through a fire exit.
As you said, I've been in major crowds at football matches, no problem at all.
I don't think I was designed for shopping ( I like markets)