Quoting Jennybananna:" Its probably something viral in which case antibiotics dont work any way. I really see nothing wrong with what the doctor did. Colds get worse before they get better."
I had a pretty serious cold of some sort and it took me having an asthma attack and a visit to the hospital before they found it necessary to do anything. I have a strong history of getting strep and they initially tested me for it only because I have had it so many times but it was negative. They only gave me Zpak for some upper respiratory infection then a sinus infection, but that was only after the hospital visit. They told me they thought I had some sort of cold/virus and there wasn't anything antibiotics could do about that. All of the doctors except for at the hospital and afterward had me wait it out, so it seems very normal that they wouldn't do much for you. Sorry you feel so crummy though!