At this point, everyone knows the most famous CFS patient, Laura Hillenbrand. Here's her story about living with CFS. http://www.cfids-cab.org/MESA/Hillenbrand.html
Thankfully, I have never been as bad as Laura's worst, though I do have days where just trying to get out of bed is almost impossible, and lately, I have been developing major headaches just from sleeping. (You read that right: I feel pretty good at bedtime and wake up with a blinding headache. Even sleeping sitting up doesn't help.)
But Laura has one thing that I don't -- a live-in support system. Where the bulk of my energy has always been spent taking care of fixing healthy meals, arranging grocery delivery, laundry, etc., Laura was free to spend every bit of her energy on writing her book, because her boyfriend took care of the chores. If she's too exhausted to get to the kitchen, she gets dinner anyway; I don't. So, I have to keep better tabs on my energy levels, to make sure that I'm not using it all on some non-essential, and then will have to go without dinner because I no longer have it in me to walk that far (only about 20 feet, but sometimes the distance feels like climbing Mount Everest).