I too had flat stools after taking that heavy laxative that you get from the pharmacy and you add water (2 litres) to to clean out your bowels for an cholenoscopy. It was awful. It was like my bowels were rejecting any food after the "draino". I was severly constipated for a week. I am no doctor but I think a persons system will reject things after a severe disruption.
You have hypochodriasis- a disorder in which persons are preoccupied with their health and fear that they have a certain disease, despite the reassurance from the doctor. Try to avoid stress, this causes pain in the abdomen. Everybody has hi/her problems you are not alone.
The pain at the right side might be appendix problem- dont freak this is an assumption.
Get well soon