"CT Scan"

I visited the hospital on 16/03/2014 for a CT scan on my abdomen and pelvis, the letter stated with 'contrast', this wasn't explained in a letter or leaflet about what the procedure would involve. when I arrived a lady brought me a jug of liquid and told me I had to drink it within the hour and then I would be canulated for more liquid to go into me, this was all a shock to me as I hadn't had any information on what would be happening to me. after the scan I was on my way home and I got major diarrhoea, I read on the NHS website that the liquid I had drank was a laxative and causes headache, again this wasn't in the leaflet or letter. I am extremely unhappy with the whole experience.