I have had a number of CT scans in the past and three this year alone. One was an urgent head scan, I had labyrinthitis into the bargain and vomited all over the place. (Too much info) The staff were lovely, stayed with me off shift and accompanied me back to the word, as they were very concerned. It wasn't stressful at all, apart from the embarrassment of being sick over them! 
There is nothing to it, compared to an MRI, it was over in no time. As cornergran said it was like having your head inside a ring do'nut.
Good luck!