Spitting Blood and stomach pains?

Around 4:30 today i started getting a stomach ache like i was hungry, and i went in the bathroom with my girlfriend when she was taking a bath and all of a sudden i tasted blood in my month so i got up and spit into the sink and there was bright red blood the first thing my girlfriend did was check and see if it was my teeth and it wasnt so we went to the ER, there the doctor said the only places it could be from is stomach nose or throat and he did nothing and said i was fine but i still feel like crap no more spitting blood but stomach still hurts and i ate idk what to do im freaking out help