I have very sharp lower abdominal pains. Along with this, I have had blood in my stool. These two symptoms have been going on since Tuesday night. Any ideas what could be up? I went to the doctor today and they did a rectal exam found no blood and sent me for a ct scan. Nothing was found on the ct scan. I came home and I still have the lower abdominal pain and I just had a bowel movement and once again blood in my stool. I'm at 15 year old female.