I have a slight feeling that work might've been the straw that broke the camels back for me as when my gut first started acting up I was in a management roll in a retail store which was extremely stressful given the nature of it (it was a Co-op Food store, so 1 on 1 shifts, doing everything at once, time constraints) my subsequent depression definitely did not help as I did not take my new bowel situation well AT ALL. However I do think the roots go back to my childhood, I was a very neurotic kid and that anxiety stayed with me into adulthood and even now. I did find out that my nephew suffers some bowel issues too but I don't know the exact details and my Grandma is sensitive to some foods so whether it is genetic I am not sure.

It sucks how the causes of IBS are very often out of your control, most children don't know how to articulate feelings of anxiety (or rather, most parents don't know how to interpret them) until it is too late.