Right, I've been on the IBS journey with one of my most beloved, and no expense was spared - the upshot is you can improve things.
Step 1= Dietician. You'll get NHS referral because that sounds hard to live with, and they're brilliant. 2 = There's some enzymes you can take before meals that calm things down. Ask GP. 3 = Take Boots probiotics (wait till 3 for 2 offer).
Wait a month for steps 1-3 to work.
4 = Exercise. No one knows why, but it helps IBS like mad. This is annoying because the last thing you feel like when you are ill and exhausted is doing gym, but at least it works.
You know this, but alcohol is a right bastard for making it worse. Why is life so unfair? Well, at least you can eat and drink everything else within reason. Don't get to the stage where you have to go teetotal because you've not cut down enough, which is what happened to one of my closest relations. She loathed it.
5 = Don't pay any attention to the internet shit about leaky gut - no one reckons it's true. 6 = Read the book Gut by Giulia Enders.
7 = Last but not least, make absolutely sure you haven't got some lingering infection in there. Ask GP for blood tests etc.