Just to throw out a different view, I woke up today and I feel great!  Of course I was up until 3am when I started to get tired and slept until the crack of noon so that may have something to do with it. 

My own experience of sleep deprivation comes from the early to mid 90's when we were all partying our socks off at raves and house parties and sometimes going 2-3 days without sleep, usually with copious amounts of "fun" pharmaceuticals. For the most part of it, I had attributed that weird next-day Twilight Zone feeling with the effects of the drugs wearing off, but since then I've come to realize that the weirdness was more the lack of sleep than anything else.
 
It really does some strange things to your brain. What I remember is that for all I felt like I was completely unfit for human consumption and dreaded having to do anything (especially involving going outside), when it came down to it my brain would go into some kind of highly charged autopilot mode when called upon to extend itself. So I would find myself in a social situation that I'd been dreading due to the lack of sleep, but actually turning out to be the life and soul of the party (and extremely quick witted if I do say so myself), or I'd find myself in a musical situation playing guitar better than I'd ever done in my life. All of this along with a slight out of body feeling. 
 
So yeah I would say that it has the potential to enhance creativity. In just the right amount it can open a sort of floodgate of highly focused ideas and thoughts. Too much and you just lose the plot. One time as a mad experiment we went 4 days without sleep. The state of my mind by the end of it scared me. I didn't recognize my friends when I looked at them, and certainly couldn't remember their names. Conversations were hard as everyone would get crossed wires and irreversible confusion would ensue. Not to mention the paranoia 

Any chance it could be sleep apnea?   My wife was diagnosed last year after suffering for years with symptoms very similar to yours.  Two unpleasant experiences driving over rumble strips on her way to work prompted a few sleep studies, where they discovered she had a fairly severe case.   She's been on a CPAP machine ever since and it's made all the difference.   She hates it, but there's no denying its effectiveness. 
 

With Bubba, I wouldn't discount alien abduction with the usual memory loss of the event either... 

bubba - I feel you pain, or numbness, or whatever it shall be.
 
Like you I've been to sleep tests (I have mild sleep apnea, sleeping on the side is suppose to be enough to solve that), and my numbers all come up good at the doctor as well. 
 
Chronic fatigue can be a sign of heart problems. Here in Canada I cannot request (and pay for) an EKG or an angiogram, etc... the Doctor must request them. I did talk him into getting me an EKG (which passed) but I cannot get an angiogram to check for blockage. Not to worry, as soon as I have a heart attack they will give me one for free ! Seriously - how is your heart condition? Or do you even know? 
 
Fatigue can also be caused by mental health issues and in particular, stress! If you wake up each day worried about something/anything, that's not good. EG, and I'll keep it short. My daughter is going through a nasty divorce and there are three grandchildren caught in the middle. My wife and I have been "tired to the bones" since this all started more than a year ago. My tiredness started long before this... but I know this is not helping any!
 
Good luck.... if you solve it, let me know what helped :)
 
Oh - and to answer your question.... my creativity has been at an all time low during all of this. I don't believe fatigue stimulates creativity at all... but the drugs that keep some people going might

if it`s any help,Dostoyevsky complained of "terrible tiredness" and whilst it didn`t seem to stem his creativity most of his stuff is pretty bleak.
imagine if he had developed a fondness for the stimulants of the day-may have helped him through the dark times he lived through and made him a tad more cheerful.
sometimes when a condition becomes chronic and is not medically detectable,you can accept the condition as the status quo,reset your standards and expectations and move forward?.
 
 
ps:getting older can create tiredness
cheers

Hi,
I just took 2 extra days off ... after my regular 2 days off ... and I could not do anything except get up ... fool around for an hour or 2 and then go back to bed. I was finally getting some decent sleep by tuesday ... but still mind tired ... and was able to actually do a lot of writing and spent time cleaning up my website!
 
That was it ... the rest of the time, was a little mindless time,  2 hours Wednesday, playing a little WoW with some close friends and family, for fun! Back to bed at 9PM to be up at 445AM.
 
Don't feel like working, and I like what I do!
 
Seriously contemplating retirement and living broke for the rest of my life, since my health is not gonna get better with the stress related to work!

I haven't had a day off (I mean a day where I don't do anything but rest) since last October...well maybe Christmas Day, but that's just a day of enforced stress. The joys of self-employment.

jamesg1213
I cannot be creative when I'm tired, just doesn't work.

'splains my missing tracks.

bapu

jamesg1213
I cannot be creative when I'm tired, just doesn't work.

'splains my missing tracks.

It do indeed.
 
Although, there are some done.