Hello and hope you are doing well.
If your symptoms are worsening with the antibiotic then the infecting organism may not be susceptible to the antibiotic. You will need to consult your doctor who may need to do a sputum culture and sensitivity to determine what antibiotic the organism is susceptible to. He may even ask for blood test and an X ray. In the meantime take OTC acetaminophen for the temperature, try to take warm oral fluids and do steam inhalations prior to your meals. This helps to loosen up and bring out the secretions.
Hope this helped and do keep us posted.
If thick sputum is causing the cough you need a good mucus thinner. Take one gram of vitamin B5 daily for a few days. That should help. Or, if you have a nebulizer, ask your doctor for a prescription for liquid acetylcysteine. Two ml three times a day with get rid of the mucus as well as any sinus condition or post-nasal drip. For me it was a miracle. I had relief the very first day, was cured in a couple of days.