Hi,
I used to get this a lot. I had very severe strictures throughout my bowel, so I'd eat, get horrific pains, then throw up. It was a pretty vicious routine. Eventually I was admitted to hospital after not keeping anything, even complan, down for a week, and losing a stone in weight!
I was put on a hydrocortisone drip for two days and that really knocked the inflammation back.
I really hope you find out what's wrong soon! I don't want to freak anyone out, just share my experience. I know it's scary when these things happen to your body and you don't know what's wrong or how to stop it, but hopefully it'll all become clear soon.
It's taken me a year of different meds, and I think now I can just about say I'm in remission. So, hang on in there!
Lucinda x
Edited to add: I should have said, I had really bad D the whole time I had the strictures.