I am sorry to hear that you have diverticulosis. I would suggest not to fast during first week of cleaning your colon with P&B shakes. But eat as much raw organic fruits and vegetables you can. If you need to include some cooked vegetables that would be fine too. Eat a healthy amount of nuts between meals. Chewing is very important for all these foods.
After one week of cleaning you may fast. If there is a way to wean off of the drugs you take that would be the best and right condition for you to fast.
Fasting will help with both schizophrenia and diverticulosis. But diet and healthy gut with right microbial flora is very important.
I think keeping a blog going is a great idea. I see that your blog is empty right now, but I am sure you will add to it with a brief of your history, eating habits and family history. Then your journey to heal yourself.