[maxk42]

It was causing a narcolepsy-like condition which caused me to experience extreme drowsiness and lethargy and fall asleep at inappropriate hours in my apartment.

My doctors couldn't figure out what it was because every time I'd go get bloodwork done, I'd be out of the house and the symptoms would clear up. I thought it was due to age and that I was simply getting tired when I got home. It took me nearly two years to realize the fatigue didn't happen when I was spending the night somewhere else. I read an article on CO2 levels affecting quality of sleep a few days ago here on HN and it dawned on me that the symptoms weren't happening when I was out of my own apartment and I'd sealed and weather-stripped the apartment shortly before the symptoms began.