Ye' Young Intestines

I am a 20 year female. I had a cholecystecomy at 16 that was preceded by four months of pain and followed by a year of severe IBS. I have had 3 years of normalcy until this past April.

I started having lower abdominal pain. I found out I have cystic ovaries and endometriosis. When I went for a CT scan to see if the endometriosis was large enough to warrant a surgery it was discovered that I have diverticulosis, with "lots of diverticula spread throughout the colon" according to the report. The GP has ordered a colonoscopy, which I'll be getting on June 25.

The only issue, besides being "so young to have so many gastric problems" is that I have had small stools with dark areas of blood, clots, and bright red blood in them. The blood is in the stools floating in the toilet, and on the wet wipe (I've had to use them since the cholecystecomy to prevent issues due to diarrhea). I'm very concerned because I do not have diverticulitis, I do not have any knew hemorrhoids, fissures, fistulas, or abscesses. Hemorrhoids, polyps, colitis, and cancer will be looked for during the colonoscopy. I am scared because I the amount of blood and ever presence in every bowel movement, plus the mucus, bloating and gas that I have. The most annoying thing is that I have a reduced appetite unless I have a painkiller, but I have to have one this week to treat the endometriosis so I can not tell how that is continuing to change.

Cancer (Kidney, colorectal, and lung), and intestinal polyps run in my family.

I guess my question is how concerned should I be about cancer?