I experience very severe pain. Is it due to diverticulitis?

Hi doctor,

I have been prescribed Mirtazapine 15 mg for reducing my depression associated with my condition. In most of my adult life, I suffered from IBS symptoms. I rarely drink alcohol. I eat fish and seafood. But no other meat is taken in my diet now. In the past five years, my problems have markedly increased. Around four years back, I underwent a colonoscopy and was diagnosed with diverticulitis. They advised me to avoid taking nuts and seeds in my diet.

Around two years ago, my situation again became worse and I have been prescribed with several courses of antibiotics. At the end of last year, I had an episode of diarrhea which lasted for a week. I was prescribed several courses of antibiotics with limited success. I still experience pain somewhat different from diverticulitis and bouts of diarrhea. I was referred to a gastroenterologist. I underwent gastroscopy and colonoscopy after consulting him. I have attached the report for your review.

One of the recommendations given by the doctor is to see a Nutritionist, who first put me on the FODMAP diet. This had a small benefit regarding pain reduction. This time, the Nutritionist recommended me to increase fiber in my diet to improve gut motility and function. So, I introduced some oats into my breakfast. After few weeks, I saw Nutritionist, who recommended me to increase more of fiber in my diet and finally advised me to go on with RPAH diet. I am not feeling confident about taking this strict diet. I would really appreciate if you could review my current treatment plan and provide advice or recommendations. I had a very severe pain several nights back and my partner was so worried and called an ambulance. The severe pain finally receded after several loose bowel movements. All of this made me feel depressed.