What Is The Cause And Treatment For IBS?

Question : Hi, I am 53 year old women , still in peri-menopause (tiny periods every 3 to 4 months). 8 years ago I had a full colonoscopy which was normal ( not even a polyp). It was done because I had change in bowel movement habits, and other stomach problems. Since everything was normal, I was diagnosed with IBS. In the past 12 months my irritable bowel syndrome has been worse, so I visited a gastro specialist several times. After a normal examination and my history he said that there was no need for another colonoscopy yet and told me how to manage my IBS symptoms. I also had stoll culture which was normal, and an anoscopy and everything was normal ( it was done because I was complaining of some anal pressure ). Less than a year ago I had a comprehensive blood work which was also normal. I have hemorrhoids, but they do not seem to bother me very much. However, my stomach is, so to say, constantly nervous and more often my stools are mushy, soft, sometimes watery ( and all of a sudden sometimes completely normal). Sometimes for no apparent reason to me I have plain, real diarrhea. It also often feels like I need to go few times a day, when I actually do not need to. As to so called red flags, I do not have blood, severe pain and in the past 12 months my weight has been stable ( I even gained 2 pounds). But, this nervousness in my stomach bothers me a lot,especially because I do not know why I get diarrhea, and I wish my bowel movements were firmer, and more formed. I am also very anxious and it causes a lot of fear in me. Please, give me an honest answer: should I go again and bother my doctor ( he saw me at least four or five times in the past year, but insists that colonoscopy is not needed and that I simply have worsened IBS.). Should I insist on colonoscopy?

p. s. This all started to worsen 12 months ago when I was under the threat to lose my job, which completely freaked my out) Thank you very much in advance