What Causes Bleeding From Penis?

I experienced a soft snap in my penis during foreplay with my penis about half erect but hadn't entered the vagina yet & then some pain on the underside of my shaft. Then a large amt of blood leaked out of my urethra & on the sheets & was dripping out. Bleeding has slowed down but still present. Do I need to go to the ER now or can it wait til the AM to see a Urologist?