The doctor said i have cystitis. he prescribed some antibiotics to stop the bleeding, but i don't see a change. ?

Possible cystitis: cystitis means inflammation/infection of the urinary bladder. It is mostly associated with pain and discomfort in the lower belly specially with passing urine. Fever/chills may be present. Urine tests can show signs of infection including blood but this blood is almost always ONLY visible under microscope, not with plain eye. There are many possible reasons to have blood in urine. See your doctor.