I've had IBS for more than a year and I know how absolutely horrible it can be, it really made my life incredibly difficult and I was trying to pinpoint the cause since I was only eating healthy food, exercising 30 minutes or more a day+ a lot of walking. Plus for a few months I had very little stress. I had tried every single type of pill and nothing had worked. Whenever I'd go out I'd have to take pills. So I attributed that to a lack of sleep. But recently it has started to improve even though my sleeping schedule is just as bad and I'm eating normally(with a few restrictions like very little gluten). And I started wondering how??? Since I'm not taking any medicines anymore.
And now I'm getting to the point. I realized that around the time I've developed IBS I was dealing with this situation in my life that was making me very angry and upset. Whenever I'd go to bed I wouldn't be able to sleep because whenever 'd think about it I would get so angry. And whenever I'd think abut it I would feel this sort of straining feeling in my gut. It wasn't causing me stress but it would make me really upset and ll that anger would go to my stomach. A few weeks ago that situation had finally reached a conclusion and I was able to move on and stop thinking about it. I felt like I was freed from a burden. Even one of my friends remarked that looked different. And that's around the time my ibs started to get better. I still deal with a ridiculous amount of stress but I am generally feeling better and I think it will continue to improve.
So basically the whole point of this really long comment is that in my case it was an outside issue that was causing my ibs and it wasn't even to do with stress cause I've been stressed(like really really stressed) before but have never experienced IBS. This situation was entirely new and it was just to do with being hurt. This was what was basically causing my ibs.
So my advice to you is to look at something that had changed in your life around the time you got ibs. Think of one thing that had really frustrated you or made you really upset around the time you got ibs, something that constantly frustrates you. It's not even to do with stress, just something that makes you upset constantly cause this might be the cause of your IBS and maybe if you are able to try to do something(if you are able to) to detach yourself from that situation or maybe talk to a counsellor or someone like that. I'm not sure if this is true for you but in my case this was the problem. Also until you figure that out I found that Colpermin worked for me as a temporary solution, like just for situations when you have to go out or do stuff like that it's a really strong medicine.
PM me if you want any more details or just want to vent.
tl;dr had ibs for more than a year, tried every medicine but they didn't work. recently it got better. I realised it was because a situation in my life that was making me very upset was brought to a conclusion and I was able to move on from it. Not so coincidentally that situation had started around the time I got IBS ( a few months before that). Then my IBS started getting better. I'm still stressed but I realized that it was mainly because of that situation that was making me upset. Also try colpermin, it's a really good in the moment remedy.