Good day,
Yes I also have this problem and for me it is mostly related to two issues.

Far easier to be exhausted!
What was a simple day in the garden before now can leave me exhausted for 2 days. A day of shopping can lead to a day or two to recoup.

Stress
More often it is Stress Overload. But now stress is measured in far lower levels:
A long visit to the doctor, concern over understanding and follow thru on paper work, worrying about things where I have no control or ability to change,

On my computer screen start up is

"God, grant me the serenity to accept the things I cannot change,
Courage to change the things I can,
And wisdom to know the difference."

😉

Some days the couch looks really good! I work hard to stay on a routine so my sleep doesn't get messed up. Sometimes I take an hour nap. If I go longer it affects my ability to fall asleep. I use a routine to fall asleep at night. I go to sleep at 10:00 and usually wake up around 7:00. I listen to my phone, playing thunderstorm and rain for sleep. It works really well. My tremors are the main problem but eventually calm down so I fall asleep imagining myself sitting on the porch on a warm summer evening watching a thunderstorm. I have saved an episode so listen to the same thing every night. I use Sirius radio. Eventually the sound of the rain turns into white noise for several hours. I sleep in the same position and keep moving my hands two different positions until they settle down. I had stopped drinking caffeine four or five years ago but recently started drinking mushroom coffee called Ryze. It might affect my morning tremors a little but I'm enjoying the caffeine boost. I hope you find a routine that gets you back on a schedule that works for you. I think consistency is the key. I no longer enjoy impulsive activity.

I have been told that it is Parkinson’s fatigue. It is usually bad for me after I have done too much the day before. I don't fight it anymore. It may take 2 or 3 days of sleeping all day, but then I am ready to overdo it again! I love that day that I feel nearly normal 😌

This journey makes to many days like you described can’t get up you don’t know why that’s what we live without knowing why ! The tests are good you’ve got this take this still feel bad you have to give it time ! Five years later you don’t have what we thought why did I get treated for it just happens life goes on and the the search continues year after year why do I feel like I do then test look good ! That’s the stories of many on this journey but finally the symptoms don’t lie if it walks like a duck it’s a duck. I’ve learned that Parkinson’s is a long journey all I’ve wanted have been what’s wrong with me I still don’t have any energy,l hurt, my headaches are 24:7 , why can’t I walk straight ? This is what it is I want answers but I’m going to go out fighting and enjoying life that I live everyday and get the most out of it that I can squeeze out of it . A new sunrise 🌅 today and more to come in this life I will enjoy all that God gives me and fight for all I can get !❤️🌅☮️

The answers/comments about problems sleeping all day are interesting. When this happens to me, it's not due to being tired. The episodes I have are that I simply cannot awake in the morning, It seems that my eyes are so heavy I can only briefly open them before they're closed again. I struggle to open them again and the same thing happens, and I can only utter to my spouse that I just can't wake up. I then immediately go back to sleep. During these episodes I will sleep and not awake until the point that my brain can function. This might be between 12 noon and 3 - 4 PM. Once I can stay awake, I'm still very lethargic and really can't do anything for the remaining of that day. The day after one of these episodes, I might be just a little more sleepy in the morning than usual and stay in bed for an extra hour or two. When fully awake, I can function relatively well and can get some things done. Two days after the episode it's like I'm back to my ole' self and can carry on with whatever I need or want to do...except on those days of brain fog. I do not drive on those days, so I complete tasks around the house, read, work on my Ancestry tree, or join a webinar, if available that day. I don't sweat about those "episodes" because I know in a day or so I'll feel much better. Cheers to all of you!!