Here are the guidelines for exercise and illness:
If you have a light headcold or light sinus infection where all your symptoms are "above the neck," you can work out if you feel up to it. But you should do a lighter, easier, shorter workout than normal so that your body isn't overtaxed. If you feel the need to rest, rest.
If you have fever, chills, body aches, extreme fatigue, sore throat, cough, chest congestion, nausea/stomach pain, then you should NOT workout AT ALL. Those are symptoms of serious illness that could get worse if you do not REST COMPLETELY.
Hope you feel better soon.