Sometimes having blood in your urine can be a sign of bladder or uterine cancer.
But other times the blood in the urine could be caused by something less serious such as bladder infection, kidney stones etc.
If the blood continues to stay in the urine after a day or so then I would go to the emergency room or urgent care to get checked out.
Or at least let your doctor know about the blood in the urine if it lasts longer than a day or so.
Normally urine should not contain any blood and if it does it's an indication of something wrong with your urinary tract, bladder and yes potentially but rarely cancer.