There was an article written by Eric Cressey about staying on track and one item he mentioned was health.
TESTOSTERONE NATION - 4 Ways To Stay On Track
"On a scale of 0-10, how bad do you feel?
If it's 0-3, you're fine.
If it's 4-5, go in, warm-up, and then see how you feel.
If it's 6, just go in and do something, even if it's just a warm-up.
If it's 7, push things back a day.
If it's 8-9, take a few days to rest.
If it's 10, you shouldn't feel good enough to check emails."
Hopes this helps. I am just getting over a sinus infection too , I feel your pain. Feel better.