for the past 3 days I've had headaches, poor balance, fever of about 101, chills, but no nasal stuff, no throat stuff, no cough, but tiredness, and chills.My physician thinks its the flu. Took Tamiflu for 2 days, but no improvement. Even when I put 3 blankets on, I shake incessantly. He prescribed Tamiflu, but this has not been a help. What can it be?