My 16 year old son throws up every moring for the pass few month he had all thoses test also and no one knows what it is. He is so sick of moring, cause he knows he will throw up 3 to 4 times. than he seems fine the rest of the day, one dr. said it was all in his head. but i don't think so
Your episodes at night sound exactly like episodes of abdominal migraine, which always come at night (often eárly morning) with strong vomiting several times and feelings of uneasiness.
Af the vomit the nausea is gone but you probably feel week. It can be triggered by food such as cheese, chocolate and lack of sleep or stress. A GI specialist will not find anything, but a neurologist with insight in migraine migth have.
It is possible to treat this with preventive medicine.
I hope this will help you!
Dr. D.A.
FYI I'm a teenage male if that helps