There’s only two times I can recall being affected by daytime sleepiness, the first was being a teenager I suddenly needed more sleep. The second time I was in my late 30’s early 40. I couldn’t stay awake. I’d practically fall asleep driving to and from work and slept all the hours I was off work. Turned out that I had pneumonia. Had no cough no trouble breathing but I had pneumonia! Weird. All other times in my life sleep has been elusive