I feel for you. I'm going through the same thing for years I have been hospitalized, multiple surgeries on my stomach and colon with no answers.
I was diagnosed 2 weeks ago.
I do exactly the same things as you. I vomit after every meal and my food just sits on my stomach and ferments, then I get extremely nauseas.
I had a gastric emptying study by they couldn't complete it bc I threw up the oatmeal.
I have had 15 colonoscopies, 8 endoscopies all in the last 2 years.
I'm am being sent to the Mayo clinic to see what they can do.
Please reply back to me..