If what I have is IBS, it started very insidiously. I had a major parasitic infection about five years ago, another one two years ago (ah, the joys of traveling in the developing world), with D 30x/day and raging fevers and oh, the most unimaginable pain, but then they subsided with treatment. Then last year, I just started noticing I was losing a little weight. Then I noticed I had some hemorrhoid-like weirdness. Then I started realizing that I was having D about 15-20x/week and thought, "Hmm, I wonder if my parasites are back." I thought for sure that's what it was. Then came the D 20x/day and bleeding and fevers again, but this was markedly different than the infections I had.
Whatever "it" is is disappearing as slowly as it came on. It's very bizarre. Exactly a year ago this started and now it seems to be wrapping itself up. I love that it's slipping away, back to the darkness where it belongs!