How can you tell if you have colon cancer or it is just really bad hemorrhoids? I have abdominal when I have to have a bowel movement, then when I go it hurts extreamly bad, there is a lot of dark red blood in the toilet, on the stool and when I wipe. Now today I just start to see blood clots. Does anyone have any clue. I don't know if I should be afraid or if it is just really bad hemorrhoids.