Hi Blood in your stool can be an indication of your IBD and I've been told that the darker the blood the further inside it is. For example, bright red usually indicates something nearer the surface, like hemorrhoids, but further inside can be a sign of something serious or just an ulcer forming over top of a blood vessel. Because it's dark, it can be in your stomach or small intestine.
I would see your doctor.
Let us know how you get on
Vern - IBD Team Member