Once I went to the driving range and I hadn't eaten breakfast first. It was 40C that day.
I felt odd but kept playing.
Eventually I had used all the balls and didn't even wait for my friend, I just felt horrible and had to get something to drink.
I walked slowly inside, up to the fridge and my vision was really vivid - bright colours, sort of waxy, not blurry just a bit fuzzy but smooth looking.... waxy - grabbed a coke and went to walk to the counter and felt increased pressure in my head, but not a fast pulse, just more pressure. Vision went really bright and I collapsed on to my knees in the middle of the floor. Must have looked horrible coz the guy looked at me like I was dying or insane or on some drugs or something lol
I imagine fully fainting is exactly the same but with loss of consciousness for a second or two after that.
Yeah, not fun. But still an interesting experience.