Lots of blood then you should go immediately. Are you throwing up? Sometimes meds can irritate the lining causing bleeding, but not in large amounts. Ulcers are tough. Most I think are caused from getting certain types (helico pylori, etc.) of bacteria from other people. You will probably need to be put on antibiotics if that is what is wrong. I would make sure not to share food or drink with another person just to be sure. Hope everything goes well, but get things checked to be certain.