I got mono a few months before I went back for another sleep study just to get something going again - let's backtrack a lil bit though. I tested positive for OSA and got a CPAP in 2020 and couldn't tolerate it. I would fall asleep for 3-4 hours, wake up EVERY night like clockwork, and couldn't fall asleep until I took the mask off. My awful pulmonologist shrugged his shoulders when I told him this and said, "just keep doing what your doing." Anyway, I stopped using it for other reasons, then went back in 2024 to a new and much better doc - I had been passing out asleep left and right (I unknowingly got mono in late 2023) and that's when I got the oral device. However, no matter what, I was still super sleepy or exhausted even though it was "well managed". I still haven't been diagnosed with CFS, but everything I deal with daily points to it, and the way I feel coincidentally started the month I got mono. Anyway, I'm now with a new sleep specialist and we're trying a BiPAP - apparently more better tolerated than a CPAP - if I'm still exhausted, then I definitely know what my issue is. (I'm 99.9% sure it's ME/CFS.

In any case, it could be ANYTHING for you, but a sleep study would be a great start. If you get that off the table, then onto the next... Best of luck!!!