Hi there! I'm sorry you're feeling this bad. From time to time I experience very similar things to what you describe, I was plagued with them for years. There are things that work more like long term, like helping metabolism, hormones, cutting out PUFAs as much as possible -extremely helpful-, but definitely there are moments when gut irritation is so bad it needs to be promptly and directly adressed. So I have my own little "protocol" for acute irritation. Here it is:
My go-to aids when EXTREME gut irritation ensues are famotidine and cyproheptadine. Combining the two yields much better and faster results, than any of those alone. Famotidine potently scavenges the already formed Nitric Oxide, which destroys membranes. It also promotes healing in the GI tract. Cyproheptadine helps me both with GI tract -it's a great anti Serotonin, and serotonin is also behind ulcers, irritation- and also helps calm down the vascular and brain irritation comming from all the circulating inflammatory mediators. The irritated gut gets leaky and endotoxin starts to travel to the liver and circulate systemically. In the liver, endotoxin prevents the correct use of sugar and thus the conversion of T4 to T3, so you get hypothyroid very fast with endotoxin, which is made evident by the cold extremities experienced. It also interferes with the use of sugar by any other tissue it reaches, making you functionally hypoglycemic. This is a good reading for understanding inflamamtion in the gut, how it translates to the liver, and as a warning against the omega 3 and 6.
PUFAs, Leaky Gut, Endotoxemia And The Liver | Gut Critters
Back to my remedies: I take 10mg in the a.m and 10 mg at night of famotidine. And cyproheptadine: 2-3 mg three times daily. I take greater amounts or more doses of those drugs if needed. Here are links for references:
Interesting properties of the H2 antagonist famotidine | Ray Peat Forum
Famotidine is a powerful scavenger of nitric oxide (NO) | Ray Peat Forum
Cyproheptadine - a wonder drug? | Ray Peat Forum
Effect of the combinations atropine + cyproheptadine and atropine + carbenoxolone in duodenal ulcer therapy. - PubMed - NCBI
I also add very small amounts of Niacinamide ONLY as tolerated (for example, 50-100 mg after meals), because it can also aid in the healing of the membrane, and it is very protective to the nervous system
Niacinamide reverses gastric damage caused by NSAID | Ray Peat Forum
My food is mostly milk (lactose free, works for me) with honey and a little broth, when I get severe irritation, and I definitely avoid acidic and possibly irritating foods, but as my GI tract starts to recover, I start to reintroduce my orange juice, etc. I would not do probiotics or fermented food, as I believe those are counterproductive, they contain irritating and anti metabolic substances.
Finally, I apply Magnesium oil over my tummy and lay down in bed for 15-20 mins. I try to do that at least 3 times daily. It's very soothing and really helps.
I do this protocol for as long as needed, but usually a few days are enough for me. Thankfully, it works quickly for me, I think because I have a better endocrine function now and better cellular function overall.
G.I irritation can get really crazy, literally. I hope you find something that works for you and get some relief.