I have had IBS for years. It started after I had water contaminated with E-Coli.
What has always helped me is not to eat after 6pm. Dinner would be very light. Making my main meal lunch.
I would have chamomile and peppermint tea an hour before bedtime. If needed a heating pad and if you can soak in a bath with salts. SO many to choose from.
I also make sure and have yogurt every day and VSL#3 Probiotic. If really bad gut, you can take capsule with meals.
You can get from Amazon but, I order directly from the site. Shipping is expensive because it must stay refrigerated.