Suggest Remedy For Diarrhea And Problem In Bowel Movement

I am a 68yr old female. I am also fit, as I walk at least 5km per day reasonably fast, do a 2 and a half hour walk once a week and hike for 2 hours once a week. Have only recently stopped running as years of various types of sports have now taken their toll on my neck. For years I have had IBS which drives me up the wall as it is so debilitating. It comes and goes, although recently is seem to be a constant part of my life. I used to have long periods of bloating with diahorrea, and even when I had been to the toilet, my bowels still felt like I needed to go back and most of the time it was mucous and wind. In the pst I would go to the toilet once per day in the morning, now suddenly the pattern has changed and I am slightly constipated (never before) which once that has cleared, turns to diahorrea and a constant need to go back to the toilet, with my back passage feeling constantly inflamed and uncomfortable. I cannot believe that this condition will get better as I get even older, and I just can t imagine life with anything worse. My doctor put me on movicol each evening, I also take colofac occasionally when everything gets too blocked, and I have espagula husks, so I have tried to alleviate the symptoms. I am due to a colonscopy in Nov, last time there was only a polyp that was removed, so other problems. I have to watch what I eat all the time, which is also annoying, as most of the time I am drinking instead of eating, and I take supplements because I don t think I am getting enough nutritian from the small amounts that I eat. I have oats every morning as oats seem to digest easily and I need energy to exercise. I have even resorted to listening to relaxation tapes, which I find extremely difficult as RELAX is not me. Which any doctor will pick up immediately. Other than IBS what is going on??? Should I be following a special diet? I don t eat meat, but lots of fruit and vegetables, fish and chicken. I eat to live not live to eat. I drink lots of liquids. I am at a loss.