Why does IBS have to be so fickle?

IBS, with which I was diagnosed in 1980 and again in 1986, often comes as part of the whole fibromyalgia / me/cfs package and, these buggers are all as unpredictable, unexplainable and illogical as each other. Take this morning: I knew I wanted to go, but made several trips under false pretences before I was able to achieve any success.

Or, as my old granny used to say:

"Here I sit, broken hearted, paid my penny and only farted."

Meanwhile, a painful tightness was gripping me across the middle of my shoulder blades (funny place for bowel fullness to manifest - I suspect it's more a symptom of toxic overload from, er, not having unloaded my toxins), the customary pain in the small of my back had reached screaming pitch, a headache was building and, overall I felt dreadfully nauseous and unwell.

I hadn't been yesterday either (which is nothing unusual), so I'd added prunes and kiwi fruit for my pudding at lunch - on top of my religiously fibre-filled wholefood menu and psyllium husk supplement regime which is what it takes to blast my sluggish digestive system into action. And yet, when I did go finally today, it was akin to a Versuvial eruption that I thought would never end and made me feel weak and unwell in the process. Now I have a stomach ache!

Why can't I get back to the regular routine I had in Tenerife where I ate a fairly normal vegetarian diet, took no supplements, yet went, regular as clockwork, with normal emissions, once a day, usually just after the 2nd cup of coffee?