I have had a change too and know I have an external hemmroid. I have had gas and flat stools for about three weeks now. I also, have pain in the rectum. Have a colonoscopy scheduled Monday. I can only pray to God it's nothing serious. I still have things I need to do.
You are doing the right thing with having the colonoscopy. I had flattened stool and just had my colonoscopy on Friday. I have internal/external hemmroids. The prep for it kinda sucked but wasn't that bad. Schedule it for first thing in the morning as you can't eat a thing. Have faith in GOD and all will be okay.