With most cases of IBS too much fiber is bad, too much protein is also bad, avoiding fermentable carbs is essential (google FODMAPS), and many health-conscious people drink too many fluid (pee shouldn't be clear) which doesn't help.
Many people are sensitive to dairy products. Lactose is highly fermentable. So is fructose which honey is very high in. If you eat any artificial sweeteners, stop - they are terrible for someone with your problems.
If I were you I'd take out the yogurt/kefir and the honey and slowly add: seafood, eggs, plenty of non-fermentable/easily digested starches from white rice (white potatoes also agree with me but that varies), and limited amounts of greens of all sorts, carrots, parsnips, tomato (all safe according to FODMAPS but play it by ear), and hard and soft raw cheeses (like Brie and Parmesan) if you like dairy. This type of diet gives you many more and varied nutrients as well as more easily accessible energy (glucose). You should be eating more fat and starch than protein (by the gram).
MY IBS and lifelong severe bloating is cured while eating low-FODMAPS 'paleo' in this fashion, it is possible! I also put on some healthy weight for the first time in a decade.
ETA: You say you are severely underweight and binging on odd foods; this makes it even more essential that you do not eat low carb and eat a highly nutritious and VARIED diet! Your body is crying out for nutrition and energy, and keeping yourself in ketosis is a very very VERY bad idea for most underweight people. Binging on honey might be the very worst thing someone with your issues can do, most honey has more fructose than HFCS.
ETA2: There's really no such thing as overeating or 'binging' when you're emaciated. It's just called being hungry. But of course it's important to eat the right foods (good fats, appropriate starches, adequate quality proteins, and greens) when you are too thin and have a high appetite, which should itself curtail cravings for inappropriate ones.
