I get that way in Walmart. One time, I didn't think I was going to get out of the shoe dept. That's where I went to find a seat, because we were closest to that area. Hubs said I was white as a sheet. My vision was blurry, and I had a headache.
It took a long time before I could stand without falling back down immediately. Hubs was with me, thank the Lord, and he left the cart there to walk me to the car. I had the sun shade on the windows, and sat there while he went back in to get the cart, and pay for our groceries. I slept the whole afternoon after that.
I feel exhausted every time I go to Walmart. I can go to another grocery store that doesn't have skylights and fluorescent lights, and not feel that bad. I'm still in pain from walking around on hard floors, because of my skeletal issues, but I don't feel like I'm going to pass out, and I don't get the blurry vision. That store is a lot farther away though, so it's not as convenient.