Just to update on my previous post:
For the past week I've been having normal bowel movements (every two days, at same time, normal consistency) without the use of fybogel or any supplements, medication etc.
What happened: About a month ago I was experiencing itching in bum area. So, searched online and saw that one of the causes is parasites (worms). But most articles were saying the itching happened at night. I wasn't particularly experiencing it at night, but had a hunch it must be parasites. Searched for parasitic infection medicines, but there were so many for different types of parasites, so decided to visit doctor (in Malaysia where I'm now).
Explained symptoms, he first thought it may be hemorrhoids, so was going to prescribe further tests for that. But I asked him 'could it be parasites?'. Then after some talk, and me explaining that I've been travelling in South East Asia. He agreed the itching could be down to parasites. He gave me three doses of chewable tablets call Zentel (each does has two tablets) to be takes consecutively on an empty stomach. I took the doses. After the second dose I had bowel movement (BM). Next bit I'm about to write may gross out some so maybe skip it.
When I checked the stool, I could see small worms (not many - about three) wiggling in the feces (I suspect there would have been dead ones and eggs also). I continued to take fybogel but the next BM (two days after) was also very smooth. Again, I checked feces and I saw one worm.
Continued with fybogel, next bowel movement was also regular and normal. So, stopped taking fybogel. I've had normal bowel movements since. Before, even after taking fybogel every night, I would have an urgency before BM (the next day). Also there was a sense of relief after BM. Now, this is not evident.
I wish this was discovered sooner because it could have prevented so much agony, from constipation, stomach cramping (I didn't have much but there was a period), going through a colonscopy, taking fybogel every night for 2 years etc. anyway, glad to have finally put it to bed. If you are having same symptoms, don't ever discount parasites from the 'causes for IBS' equation.