I call it a good day when I have enough energy to do little things (make some breakfast, feed the cats) without getting too exhausted. Exertion always leaves me short of breath, but on a good day I can recover quickly when I rest. On a really good day, I can take a shower and get dressed!
On a bad day, I'm exhausted even without doing anything, and it's hard to catch my breath. Any exertion seems too much of an effort. I find myself drifting off to sleep a lot.
I can usually tell, when I wake up, if it will be a good day or a bad day. When I can put together a string of good days--recently I had a string of nine--it makes me feel much more hopeful. People have commented on how well I am handling things, but I don't know any other way than taking it one day at a time and trying to get as much pleasure out of each day as I possibly can.