Suggest Treatment For Ear Infection

I have had no previous ear problems, however 6 weeks ago woke to the sound of my heart bet in my left ear I vistied my GP who advised i had an infection and prescribed Ammoxcillin 500g to clear this. He also informed me that the sound i was hearing was due to fluid in my middle ear and this would go away with the medication, but it has not and is now causing me concern.