Why did I vomit earlier?

I ate before going to sleep. Enough to make me full. Then I just chilled for a little and went to sleep. I woke up and felt nauseous. Then I threw up, it was so much and it had so much pressure that it was almost projectile. It was also very acidic. I saw some of what I ate. I was thinking it was because I just went to sleep almost right after eating, but I am being told peristalsis does enough work for this not to happen. And I'm not pregnant.