Question 1
Did you feel like going to work or school or doing chores today?
If no, you probably should not run. There was a rule I always had when I was growing up: If I had to stay home sick from school, I had to stay home sick from everything else. Along that line, if you weren't well enough to go to work or do whatever it was you should have been doing on a normal day, then you shouldn't be well enough to run. Also, if you did go to work and you felt horrible all day, you probably shouldn't be pushing yourself by running, when you could be resting.
If yes, go to question two.
