I would say go get it sorted. Ive just got over a kidney infection. OMG it was awful, two courses of antibiotics to get rid of it. My back was sore and trying to go to the loo!!!!!!!!!!!!!!! Your doc should have given you something there and then cos Kidney infections can be dangerous. If you can go to ER i would. Its so painful and uncomfortable I wouldnt imagine you could wait very much longer.

In the mean time drink lots of water and cranberry juice, it really does make it a bit easier.

Take care

ATG