I understand your confusion and concern about having microscopic hematuria without any STD or UTI. It's good to hear that you underwent a cystoscopy, which is an important test to evaluate the bladder and urinary tract. The negative results from this procedure are reassuring as they indicate no visible abnormalities in those areas.

Microscopic hematuria can sometimes occur due to various reasons other than infections, such as kidney stones, vigorous exercise, certain medications like blood thinners, prostate issues (in men), or even strenuous physical activity. If your healthcare provider has ruled out STDs and UTIs through appropriate tests including the cystoscopy exam but there still seems to be persistent microscopic haematuria present; it may be advisable for them consider further investigations or consultations with specialists if necessary.

It's essential to continue working closely with your healthcare provider on exploring potential causes of the microscopic haematuria so that accurate diagnosis and proper management can be achieved.
Feel free reach out here if more questions arise!