My holistic doctor used to say you should always stay home for 24-48 hours when you are sick - that is when you are most contagious and also when you can control how long and hard the sickness overtakes you. Rest! The best medicine. And stay away from all caffeine, processed sugars and fats while sick. Drink LOTS of fluids, but nothing caffeinated.
Best of health to you this cold and flu season!