I know this is so frustrating. I am on the Low Fodmap diet. You can download the Monash university app from the App store so you know what and what not to eat. Mind you, there is no a "one size fits all" management when it comes to IBS. What affects you may not affect the next person.
It also helps to note down what you eat, so you know what irritates your gut. Eliminates what triggers your symptoms. Fermented foods help with symptoms because of the probiotics produced during fermentation. The probiotics help to balance the friendly bacteria in your gut and alleviate some digestive problems. Try to drink kaffir before and after meals to prevent flare ups.
I hope this helps.
Cheers.