How do u no if ur stomach is bleeding inside?

Hard to know.: It depends on how much you are bleeding, and where the blood is coming from in the gut. If it is a slow blled, the only way you will find is is that you get weak. If it is high up in the gut, you may not see blood in your stool at all, or the stool may turn black. If it is low in the gut, like hemorrhoids, you may see blood in the stool, or the water in the toilet will turn red when you do #2.