First of all, I should start by saying I myself don't have cancer nor am I being checked for cancer but I stumbled across this forum when researching colonoscopy reviews and now I've had mine (to see if I have Chrones Disease) I thought I'd share my experience to help anyone out who wants to know what it's like to help call your nerves. 

I had my procedure at 9am on a Sunday morning, so on Friday night I had to take 6 senna tablets. These give me a bloated stomach within 20 mins but that wore off within half hour. I took them just as I was going to bed, and when I woke up on Saturday morning I had to use the loo

I was allowed a breakfast (low fibre) before 9am then after 9am I was not allowed any solid food at all (all I drank after this was water and one cup of black tea with sugar)

Started MoviePrep at 5pm (first litre) and drank this over an hour. I actually liked the taste, so drank this without any problems. Nothing happened till 19:20 when toilet trips began. Had my second litre at 8pm and remained going to loo till 11pm when it calmed down and I went to bed and slept through. For 4 days prior to Sunday I followed a low fibre diet which I think made the prep easier. 

Woke up early next morning (day of procedure) and had 1 more toilet trip. Got to hospital for 8:10am and was in procedure room by 9:05. The camera honestly is nothing, no discomfort when they put it in, and only some slight discomfort during procedure which I used gas and air for (but I only used it as it was available I could have managed without it) 

I had 6 bopsies taken (you can't feel these) and the whole procedure was over within 30 minutes. I Was out of hospital less than half hour after test finished and was in a local pub having a breakfast by 10:30 (due to not being sedated)

im a 33 year old male 

i hope my post helps alleviate any fears you have. Honestly it's nothing and the NHS staff who will deal with you are lovely (although I was too engrossed in watching the images of my bowel to talk much to the nurse haha)