I think I have the flu. But I ve never had so many muscles aching. I ve had knee problems and plantar fasciitis in one foot. All three have flared up badly in the last day or two, My temp went up to 102.5, it s now down to 101.2. I keep shivering, even though I am in a warm room and drinking hot tea I have no appetite but I choked down some hot soup yesterday and half a slice of toast today, I am female, 67, and in very good shape. I have almost never had the flu. Is this what I have? How long will it last?