Hi Meaney, though my primary cancer is prostate it was also in my bowel, tiredness as you call it, also called fatigue is common with certain cancers and the bet way through it is exercise, sorry i don't now what variation  or how many sessions of radiotherapy you will have, but you will find the radiographers the nicest, most helpful and caring people you could wish for and will answer any questions you have. I saw your posts on another forum and like you I am terminal and just wanted to say, i know it is difficult to talk about it, but it really helps and should you want to talk to someone who understands i would be happy to talk, best wishes.

Eddie