Ah- just saw this- I have these sort of symptoms but can not tolerate psyllium fibre - it really aggravates symptoms for me :(. I kinda feel better knowing it really does work for some . Wish I was one !When I first started taking it, it affected my bowels. I almost stopped taking it because since I already have IBS-D, I didn't need the aggravation but over time and after I started more diligently taking a psyllium fiber supplement daily (as I should with IBS-D, anyway) the problem went away.
I find I tolerate fruit and vegetables better when cooked ( but love them raw ) .
My gastroenterologist described ibs as being fibro of the gut when I was under investigation - it always struck me as an interesting comparison but I get it more now .