Hello! I have been through your question. Related your concern, don t worry because you should know that taking antibiotic for 48 hours it is not enough to have a fast improvement.You should wait more than 3 days to feel the first relief. Except of this you should be sure that amoxicillin is the right medication for this situation talking with your doctor, doing a physical examination to make a differential diagnosis between a strep throat and tonsillitis (viral or bacterial) and take a throat swab for culture to find the cause . With strep throat, the sore throat is often more severe and persists and is caused by streptococcus bacteria as well as bacterial tonsillitis .However in your case I exclude a sore throat from a cold because often gets better or goes away after the first day or two without antibiotic ( you say that have sore throat for several weeks) and is associated with some cold symptoms, that you don t have. Usually for strep throat or bacterial tonsillitis I prescribe amoxicillin (augmentini) or ampicillin( if you aren t allergic) for 10 - 14 days and after these days you should finally expect total improvement. I hope my answer help you. I wish you a quick recovery.