A) Carbon dioxide
I actually had carbon dioxide poison once. I started feeling funny then my heart started pounding then my eyes was hard to keep open. My head wanted to keep falling. It happened at my home. First, all was telling me to lay back and take a nap. I said No, call 911❗ My heart felt like it was on the outside of my chest.
Hospital said I had carbon dioxide poisoning and I was the alarm for my two little kids and doggies. We had a very small pin hole in our furnace! We didn’t have a carbon dioxide alarm, but we bought one that same day.