Overheating at Work: Is it Normal?

Does anyone else get overheated more easily than those around you? …I at first thought it was related to my weight but a few other people I work with are heavier than I am and don’t seem to have these same issues. I work at a pizza place with 800+ degree ovens (Fahrenheit), AC that barely works, and recent high 90s temperatures. Obviously that would make most people sweaty but I feel like I have a stronger reaction to the heat. Today it was the worst it has been. I often get slightly blurred vision, feel light-headed, and get a headache (though I generally get a lot of headaches anyway). Today I also felt nauseous and had some stomach pain. I drink tons of water but it doesn’t seem to do much aside from make me not thirsty. My dad was working today and could tell I felt bad so he let me take a break in the walk-in fridge. I IMMEDIATELY felt better in the cool and felt pretty awful again after a few minutes in the heat.