There are many reasons why you may have blood in your urine (Hematuria) such as urinary tract or genital infection. I think you should also find out if you have something blocking your urinary tract such as a kidney stone. You have had a ct scan and it showed nothing so it is unlikely to be a tumour. Other reasons for blood in the urine are diabetes, medications such as certain antibiotics, trauma to the kidney and kidney disease
The colour of the blood in your urine is affected by diet, medications and disease.

