Big box stores, Walmart etc. After 10 minutes I feel like I'm getting the flu. Weak. Headache. Fuzzy. I hear it from other people too. They attribute it to the lights, security system, plastic fumes...
We used to joke that they have a giant soul-sucking machine in the basement.
Sounds like anxiety, possibly social or stimulation. Do you get like this in other super crowded locations that are not enclosed (think open air malls, concerts, etc.)? What about in a location that has constant background noises, but you're alone or with very few people?