How we use our bodies has a lot to do with determining how we feel. Generally, the more sick you act the more sick you will feel.
When you are sick, do you allow your posture to slouch, your feet to shuffle, and your breath to become rapid and shallow? Or do you hold yourself open and aligned and allow your movements to glide, no matter how slowly? This will go a long way towards determining how well you feel and how quickly you recover.