[Blindsight]

Go and try to work out with the mind set that you're going to get through it and have a good workout anyways. If you feel too worn out to put forth a good effort on anything, then you shouldn't be there... go home and rest more.

In my experience, this is the best way to recover from a minor sickness because until you actually get in there you have no way of knowing for sure how it's gonna feel. At least you can feel good about the fact that you took the initiative to try to work out and are not just lazy (I have to convince myself of this every time), and that your body truly just needs more rest. Also, if you don't at least test the waters, you may take off more days than are really necessary.