At least you had time to prepare. I suffer from Ulcerative Colitis. At my first outpatients appointment when asked by the specialist nurse how I was? I replied "fine" My wife helpfully chimed in "no you're not! you've been to the loo three times while in the waiting room!" The nurse then stated "oh thats not good. Lets have a quick look while your here." Result was unexpected camera job there & then. My wife still reminisces about seeing the markings on the camera disappearing under the sheet as the consultant got to work..
As someone with a bowel disease, I classify myself as a bit of an expert here! My 2p
Colonoscopy - Take the sedation
Flexible Sigmoidoscopy - You'll be fine with nothing
Ooof, I had a Cystoscopy recently. it was nowhere near as bad as I thought it would be, if fact it made me laugh when the guy got a paper sheet and just poked his thumb through the middle of it, then placed it on me if you know what I mean! All i could then think of then was little rooter poking through a hole, It must have looked like a leftover cocktail sausage at a kids birthday party tea!
But as Tashy said, GET IT CHECKED. No more taboos in poo and lumps, if in doubt, get it checked.