First, I'd like to say thank you for writing this. I'd also like to add a little for others who may be in a similar situation.

Just to set the background, I'm in my mid-40's, was a responsible adult, and had a house and family, and worked as a programmer for 15 years. I was fairly typical as a programmer -- a bit overfocused, had an excellent memory, strong reading skills, etc... I wouldn't say I was a great programmer, but I was a solid, competent programmer at the senior-ish/lead level.

Initially I was diagnosed with sleep apnea. Once I was on a CPAP machine I had periods where I'd sleep more-or-less normally, but I'd still go for periods or three to six months without normal sleep. This went on for three years or so. During periods of extreme fatigue my immune system would collapse and I'd get sick at the drop of a hat, and normally small things would make me really sick. Well, that was pertty horrible, but not too bad, really. I could get through it and, once the CPAP was set up correctly I'd eventually come back to normal after a few months.

I'm not really sure, but I think that sometime in that period I picked up a disease like chronic fatigue syndrome or mono or something that made it so that fatigue and confusion cause real trouble in my life. My memory is crap, and is simply gone most of the time. I have an extremely hard time getting focused and oriented. It's destroyed me financially, emotionaly, and caused a whole bunch of damage in my life. I'm just barely getting by and living in my van.

Sometime I'm better than others, but I go through these periods of extreme fatigue, where I mentally "fade out". My memory gets extremely bad and I forget things within seconds or minutes. I have trouble recognizing faces, names, etc... as well as just getting myself organized and functioning like an adult. There are periods where I come around and my brain starts working sort-of normally again, but it doesn't seem to last for very long.

I've seen seven or eight different doctors, ending three years ago when I lost my job and ran out of money. I didn't had any luck getting any of them to take my condition seriously. I'd tell them that something other than sleep apnea is going on, but they can't find anything, at least nothing obvious, so they don't believe anything is really happening, that it's "just psychological". But I know my self better -- for example I Know I had a college level reading ability in the sixth grade. Now I have trouble remembering the title of a book I read a week ago.

I'm solidly in the "darkest fears made manifest" stage of this thing. Part of me knows I'll survive this, that this will pass and that everyone deals with sickness, old age, and death. It has been (very) slowly getting better. I still have bad periods, but they aren't quite as often or as long, or as bad, as they were several years ago. Even still, when I'm in the middle of one of these periods of fatigue and confusion I'm convinced that it'll kill me.

So, and here's the real point of this, I'm still committed to being a force for good in the world. I'm there for my kids, regularly volunteer, and stay involved with helping other people. Like you say, mortality is the ticking timer that keeps you alive.