dear user about your question i would like to tell you that urinary tract infection may be due to viral or bacterial infection from your words it is almost due to bacterial infection and the treatment fail to complete eradicate thae bacteria......this because you may have not completed the course of treatment or you may be described inapprobiate antibiotics..........differnet and multible antibiotic administration lead to having resistance for treatment ...as the bacteria accomodate gradually to resist antibiotics then symptoms get worse......spots of blood you found and pelvic pain you feel is acommon symptoms of bacterial infection and if we treat the cause improvement will occur rapidly.....my advice to you is refer to urologist and doing urine cultura and antibiotic sensitivity tests these tests will detect the causative organism and will detect the suitable antibiotic for treatment .....you need not to worry about kidney as having urinary tract infection not mean kidney problem but should be treated to avoid complications..........wish you healthy life