I have diverticulosis and had a nasty bout of diverticulitis a couple years ago. You asked if having one episode means you will have another. The answer is not necessarily, but having diverticulosis increases the risk. I make sure to get enough fiber in my diet and so far have avoided another attack. Seeds and nuts do not bother me. The one thing I did when allowed to eat solid food again following that attack was to introduce foods slowly to see if any one food caused me additional problems. I hope you feel better soon. I was so sick I spent 10 days in bed or on the sofa. Of course I am hardheaded and refused to go to the hospital like my PCP wanted - LOL.
There is good information about
diverticulosis and diverticulitis here:http://digestive.niddk.nih.gov/ddiseases/pubs/diverticulosis/
The Mayo Clinic also has good information on diverticulitis:http://www.mayoclinic.com/health/diverticulitis/DS00070