What Causes Blood In Urine And Urgency To Urinate?

I can find minute amount of blood in my urine and there is blood seen on my underwear. When I just start urinating is when d blood is seen.. There are blood clots seen once in a way.. There is no pain. I feel the urgency to pass urine and can't hold it for long. And I have put on lot of weight.and I haven't got my periods from 2 months