What Causes Irritable Bowel Syndrome Along With Diverticulitis?

HI i am a 70 yr old female who has had these symptoms for over 30 yrs had many colonscopys have said irrital bowel , last thing was divertilous .. i have atleast 6 loose stools a day most the time terrible cramps and so much gas , i am also house bound and have been for so long , only time i can leave is if we take a camper and truck so i have a bathroom , for whatever reason the last 3 weeks it is even worse , i have taken one drug that helped but they say i am over 60 it could make me fall ? so i can not take it , sorry if i heard the name i would know what it is , it did help some , the gastrologist gave me a powder i took with water , it did not help took it over a year , any suggestions , i am getting so depressed , i have no life , thanks so much