I've had a throat infection for a week now, and it wont go away! My tonsils are SWOLLEN and painfull!?

It started on Tue. night, so I started on Amoxicillin. The next morning it was worse, so I kept taking the Amox. to see if it would get better, but it didnt, so I went to the doctor, told him this, and he perscribed something else, convinved that the infection was strep. However, Ive had these before, and they werent strep. This time around theyre a lot worse, though. Now Ive been on azythromycin for 4 days, and it just spread to the other side of my throat (at first it was only on my left side). NO signs of getting better. WHAT can it possibly be?