Hey, I have something along these lines, it's awful. I think it's triggered by the vagus nerve stimulation?
Mine usually starts at 4-6am, get up to go the loo. Then the immense pains start and it turns into bad D... sorry TMI!! My ears go muffled like I'm under water and my eyes go speckled, like white noise.
The odd time I'll throw up at the same time.
At that point I am boiling hot yet freezing cold, I'm drenched and usually have to strip off to try and cool down. But then I'm also shivering like crazy. I'm also struggling to keep myself up, almost fainting, and have fainted sometimes.
It tends to last 30min - 2hrs. Aftwards I am completely drained, drag myself back to bed.
I think it may be set off by food, since I've cut yeast out it doesn't happen as much. But saying that, I kept a mySymptoms food diary for almost a year and found no real link between food and these attacks. Yeast does make me unwell though.
It's a scary thought as it's out of the blue, I'd hate to be in that situation if I was out an about. It has happened during the day once or twice.
I've had several Drs say that doesn't sound like IBS at all, and others just shrug it off. Either way they don't do anything. Google IBS and vagus nerve. It was something similar to this happening during school time that got me on the pill 13 yrs ago too as well as regular period pain.