5 days a week I do strength training (pilates). And everyday of the week I walk(incline) and run. Anyway, I've come down with a cold and my bones just ache, most days when I'm sick I can usually hit the tredmill or at least go out for a walk. But today is not one of those days.. So my question is, is it OK to not really get any exercise on days where your really sick? I think my body might just be telling me its tired and NEEDS the rest, but I would like any inputs.

Doctor's rule of thumb. If your symptoms are above the neck (sniffles, runny nose etc) then you can keep working out. If they are below the neck (fever, chest tight, aches) then stop and rest.