I'm waking up in the middle of the night with vomit in my mouth, and gasping for air..

Ge reflux. There may be more than one issue. Gastroesophageal reflux accounts for the vomit in the mouth. Contributing to this could be hiatal hernia and esophageal dysmotility. If this happens a few hours after eating, then slow gastric emptying or gastroparesis can be another issue. You should see gastroenterologist.