I had IBS flares for a long time. It was worse when I was under the most stress, but not correlated exactly. What seemed to help was low-dose prozac. Gut-serotonin link of some kind. I've stayed on it, even though I have more effective meds for depression now, since the IBS has stayed mostly quiet.
and yeah overall it's not serious, but I spent a lot of time being afraid to leave the house when I didn't know for sure where I could get to a bathroom. Or would just feel too exhausted by symptoms. It impacts daily life.