Why IBS is periodic and unexpectable.

Due to weight loss and unhealthy eating habits, I developed symptoms close to IBS. Stomach always make sounds and periodically like for a week or 14 days, I will have a hard and loose stools. My body always make sounds like I'm having diarrhea but mostly not. So I started listing the food dairy and symptoms were reduced but I feel like any time anything might happen which is making me not concentrate on work or plan trips or attend business meetings. Is there a way to come out of it? Should I think more about it or let it go until something severe happened to me? Should I reduce stress due to overthinking about my health? Do IBS is just a lifestyle disease with no cure, so I just need to manage symptoms?