I go to work. Most of the time, that can be a good thing, as many illnesses, while inconvenient, are minor. Sometimes, though, it makes it worse to man the [censored] up and keep going.
Once, I had meningits, didn't know it, went to work. I woke up in a hospital room. I'd told the bf to turn his music down the previous night, because noise, light, simply exisiting was excruciating pain. He'd taken offense. I didn't want to be percieved as a wussy ass girl, so I said nothing. Went home, hurled, went in to work, hurled, head still hurt. Took a prescription migrane pill. Resumed working. Next thing I knew, I was in a strange room, and the nurse informed me had to lie flat on my back. I was there almost two weeks. Couldn't eat, slept a lot.
I find that sleep, lots of fluids, and knowing my limits helps me recuperate much more quickly than trying to motor through as if nothing is wrong.
That's basically what I try to do, that is, the latter. Usually I don't try for too much sleep, though