How I know when I am really sick

I cannot explain it. There must be some physiological reason for it. Maybe someone can explain it to me. When I get really sick with a heavy cold, or bronchitis, or a nasty sinus infection, I not only lose my taste for coffee, I am repulsed by it. Recently (as you may realize from the lengthy interval since my last blog entry) I had sinusitis. I am still not 100%, but I know I am on the mend.  I can stand coffee again. There was about a 5 day period when the thought of it was revolting. I wasn't terrible hungry anyhow, but when told to drink plenty of fluids, one of those fluids just couldn't be coffee...yes, tea, herbal tea, water, juice, but no coffee. It would have been torture. These mysteries in life, with no seeming explanation.  If anyone has a scientific reason for coffee aversion during illness, I'd love to hear it.