[throwaway34241]

You say you've seen the doctor, hopefully that included seeing a sleep specialist and having a sleep study done? Sleep apnea is very common, and people can have it even if they do not snore and are not overweight (although gaining weight is a major risk factor). And in earlier stages patients may not even have apneas, they just move out of deep sleep.

Maybe you've already been checked but I just thought I'd mention it since it's a very commonly overlooked diagnosis (an estimated 80% of cases are not diagnosed), and declining sleep quality and falling asleep during the day are major symptoms of it. I have a relative that eventually got treated and it made a major difference for them.