Can gerd cause you to vomit in your sleep, when you are unaware and you only wake up because you are choking on it?

Kind of yes: If you have bad reflux, when you lay down there is no gravity keeping your gastric juices and acid in your stomach. The acid will migrate up your esophagus and can cause a feeling of vomit or choking when you wake up. You need to be evaluated as well as change certain lifestyles such as raising the head of your bed while you sleep. An upper endoscopy is essential for your exam.