I’m struggling to understand where they are coming from

I was sitting at my desk yesterday, and trying to do some work.  Every time I began to get something started, I would fall asleep.  I knew that I hadn’t slept very well that night, so I blamed it on lack of sleep.  The next day, the same thing was happening. I had slept a full eight hours, so I wasn’t sleeping.  I thought maybe I needed another cup of coffee, but I had already had two. I called my husband at work, and I told him about the sleepiness.  I told him that I thought there could be something wrong with the ventilation system in our house. Even though this wasn’t happening in any other room, my room was small and it was right above the basement.  When he got home he got checking to see if there was something wrong. He checked for leaks in the gas. he checked the furnace. When nothing seemed to amiss, he called the HVAC company. They came out and went over the entire system for our gas furnace.  He was thinking there may be a leak somewhere inside the furnace that was causing carbon monoxide to come up into the room. Finally, the HVAC tech went out to look at our hot water heater. I didn’t know there was exhaust that came from the gas hot water heater.  There was a small leak in the pipe and the exhaust was coming right up into my office through the floor. I was suffering from carbon monoxide poisoning. It was such a small amount that our carbon monoxide detectors wasn’t picking it up. It was only in my office which is kept closed up all of the time.

HVAC company