Many things. Blood in the urine is not normal and it could be a sign of underlying urinary tract problem. These include stones, infection, or cancer. Blood could also be from the female organs as well. You need to be evaluated by your medical doctor to determine the source of the blood.
Many causes. There are many reasons but most commonly this is related to a bladder infection. Other more serious problems like cancer of the genitourinary tract or bleeding problems can cause this. You should see your physician to get this evaluated.