I Am 29 Years. I Had FLU And Went To

I am 29 years. I had FLU and went to the doctor last week Monday. Got injection and Antibiotics. On Thursday then I started having a bitter taste in my mouth and feel like I can just drink water and not eat. I urinate a lot, but I think its from the lot of water I drink. I have never drank water at night but now I wake up and drink water and not just a cup, like a jug of water. What could be the problem?