I 100% agree with the advice given by ipnotica. I suggest that you ask for a colonoscopy and maybe at the same time, an endoscopy since you are experiencing pain in your stomach too. Both procedures can be carried out while you are under the same dose of sedation.
Good luck
Morecambe
You need to see a doctor. I had the same thing about a month ago and I ended up in the hospital for 4 days. They still don't know what's wrong with me, other than the fact that the CT scan showed that I had colitis. I'm scheduled for a colonoscopy on the 9th.
I think the doctors are thinking I have diverticular disease or ulcerative colitis, but I'm not sure. And of course they want to rule out colon cancer. All I know is that severe pain and bloody stools is not normal and you need to find out the cause, and the sooner you do the better.