about a week ago i was having the urge to go to the bathroom every half hour, a few days later i started seeing blood only when i wiped, then i started seeing drops of blood in my urine and it hurt so bad to urinate, i went to the doctors to see what was wrong and took a urine test but there was too much red blood cells to see anything else. they did a over night culture of a different sample and there was no infection. the doctor has no idea what caused it. does anyone know what might have caused it?