Proctitis or Diverticulitis?

I was diagnosed with crohns almost ten years ago. I have had two colonoscopies with the most recent being two and a half years ago. That one showed no sign of crohns but did say I had diverticulitis. It must not have been too serious as they did not prescribe me anything. I have since been gluten free. The gastroenterologist thinks I have IBS with mild crohns. The other day after eating lunch I had a sudden pain in my lower abdomen and had to rush to the bathroom. I had a bad case of diarrea and went again a half hour later. Since then I have had a lot of lower left ab pain. Not constant but a lot of the time. I feel like after I go to the bathroom I still have not emptied my bowels and have the constant urge to go again. I also have some slight rectal pain. I have had this in the past and it has gone away after a month or so. I called my doctor and spoke to the RN to get some cortifoam because I am thinking it may be proctitis as he has said in the past he thought it might be proctitis. Then I got to thinking that maybe it could be diverticulitis since they found it on the colonoscopy a few years back? If this cortifoam does not work I will call him back but was wondering if those symptoms sounded anything like diverticulitis or more like proctitis. I have no fever and am eating fine.