You need to get a CT scan of your paranasal sinuses. Unless you are suffering from AIDS or any similar disease which causes severe immune compromised status, at your age primary tonsillitis is not possible! It is most probably secondarily infected...so the CT scan will reveal the primary focus of infection that needs to be cured to be finally rid of this infection!
This should have been done by your previous doctor. As he has not done it, I would suggest you to use this app to search for another ENT Specialist in your neighbourhood who has good patient feedbacks, and fix up an instant appointment