How To Treat UTI Inspite Of Taking Cephalexin?

Have a urinary tract infection since released from hospital the end of January. Have seen primary doc on 2 or 3 occaisions since then, peed in cup, doc said whited blood cell count was not what it should be and ended up prescribing an antibiotic. After taking 2 of those a day for 7 days, it came back within 2-3 after finishing rx. On,3/10 I was back with same problem..urgency and very painful! I picked up Cephalexin 500 mg capsules (qty 40-took 4 a day till gone on 3/20. Here I am 4 days after finishing it and the problem is back with a vengeance. What is going on that the meds are not clearing it up? Could there be something else wrong? But I know the symptoms of urinary tract infection and that seems to be what it is. Any ideas?