Without going into great detail, I had been diagnosed with diverticulitis and IBS several years ago. I stopped eating what the doctor told me to: corn, popcorn, raisins, and nuts. He never mentioned staying away from seeds, so I continued to eat foods that had them. Even though I watched my diet, I ended up with a perforated bowel in July of 2011. In the emergency room, they told me I had to have a temporary colostomy. They did the reversal three months later. I still don't eat any of the things my doctor told me to stay away from, and I added seeds to that as well, but I still have periodic symptoms of IBS, probably brought about by either medication and/or not enough fiber in my diet.
Prayers for you, and make sure you follow up on that doctor's appointment, and do what they say.
Trust they ruled out Celiac Disease as well....Diverticulitis and IBS are too often diagnosed as the problem when in fact Celiac Disease is the real culprit.