hi there, as suggested by your doctor do take a repeat urine exam done and also ask for a culture and sentivity of urine.If you still have blood in urine you should visit a nephrologist
and get yourself thoroughly investigated as you rightly have seen that ca bladder could present with asymptomatic hematuria
besides genital tuberculosis
and other hordes of kidney
problems which may present with blood in urine. Its best to get yourself evaluated and put your mind to rest rather then imagine the worst and lose sleep over itl; Take care.