symptons continue after treatment

I got a bladder infection about 6 weeks ago. I know how I got it. I did not pee after having sex, which has been a problem for me before. The next morning when I went the the bathroom, it was obvious what the problem was. Went to the doc, had urinalysis, positive for UTI, took Antibiotics . After the course of Antibiotics , symptoms continued, but not as bad. Asked doc for more Antibiotics (knowing I was doomed for a yeast infection) but took another course. Still no relief. Symptoms now are not nearly as bad as onset of infection, but still noticeable. Definite buring in urethra after going pee. Worse while sitting down as if pressure makes symptoms worse. I have done natural remedies like cranberry etc. Went back to doc and tested for UTI and STD's, all negative, but symptoms remain. I know it is not BV, have had that before and symptoms are not the same, it is not yeast, there is no itch. Could my urethra be damaged from the bacteria of the antibiotics themselves? What can I do to relieve this problem. I have an appointment with a urologist but want to try to fix this myself as I do not believe there is anything wrong with my bladder per se, it's just some "after-effect" from the bladder infection---FYI, my tests were all cultured, so pretty sure no infection present.