The symptoms of lower gastrointestinal (GI) bleeding actually indicate another condition. A change in the color and texture of your stool could indicate that you are passing blood from your lower intestine. The stool may appear to have blood in or on it or have a tar-like appearance. Some minor lower GI bleeding may not be obvious, however. You might feel a little tired or weak and even be dizzy. If you lose a little blood over an extended time from undiagnosed lower GI bleeding, you may become anemic. Extreme lower GI bleeding could cause cramps and abdominal pain, a drop in blood pressure, and difficulty breathing.