sore throat and cough?

Hi all, last night i went to my GP as i have been feeling really down. He told me i have a viral infection , i have a sore throat , ear ache and aching gums.
Ive been ordered rest and iron tablets as he said i looked anameic, I had very low iron levels in my last pregnancy.
My glucose test has come back normal.
Today I have slept and slept, My dear DH has waited on me hand and foot, but i just feel worse.
The gp has told me to sleep propped up and to drink heaps off fluid, but if i develop a cough i have to go back with a urine sample.
He said anytime i devlop a cough and sore throat i should take a urine sample to a GP..
Why is this?
Im a bit worried now