Hi, I Have A Question About Bloody Urine. I'm 54

Hi, I have a question about bloody urine. I'm 54 years old, and don't smoke. I have a history of hypertension. I had blood in my urine about two months ago, and went to a doctor the next day. They took urine, and found only traces on microscopic blood. They took an x-ray of my mid section and found no stones (and I assume no tumors). I was told that I have high BP, which I have gotten under control...It was around 180/95 and now typically 127/72. Anyway, I started using test dip-sticks, with little problems since. Tonight, however, after moving the lawn and pushing uphill, I had darker urine, so I tested it and it was high. An hour later, it was clear. I'm concerned about bladder cancer.
Any advice would be appreciated. Thanks!