Before you launch into any specific diet, you need help to work out what is triggering your episodes. It is likely to be stress alongside something else which might range from animal fats to husks on seeds and pulses - I'm speaking from experience of a family member.
The nature of the diverticula - the little baggy pouches that develop in the bowel - means that waste can literally become trapped and infections can result, so do as others have said and get yourself examined.
Good luck and get well soon.