Please help me diagnose

Health counseling description:
Me two months ago and fever appear soy sauce color hematuria, two days after the disappearance, but has lower back pain, for routine urine examination, occult blood, red blood cells occasionally or 3 to 4 normal, B super-normal, go to the Department of Nephrology, see a doctor, the doctor said nothing, low back pain and it does not matter, I am a medical student textbook investigation discovered quite like IgA nephropathy, very afraid, I would like to ask addition to nephrotic outside, the fever can cause hematuria Why, back pain, and it does not matter what, thank you doctor as soon as possible can reply.
Doctor: Hello: it is best to do a B-check! See bladder no problem