I had a sore throat about 5 weeks ago. My tonsils were red and swollen and I had a terrible headache. Then it kind of went away, but suddenly the right tonsil just flared up again. About 4 days later it went away. Then the left tonsil flared up. Again it went away. Now, in my fifth week of trouble, I have a gland in the middle left side of my throat that is extremely sore and my head hurts again. I am also incredibly tired all the time. Should I seek a doctor? I did initially and I tested negative for strep. But what else could this be?