I usually only feel nausea when i lay down to go to sleep. i am almost fully asleep and then i wake up to sit up and take deep breaths or else i feel as though i may vomit. i tend to burp afterwards and then wait for it to calm down before sleeping.

Nausea: I assume pregnancy is not an issue. Nocturnal nausea may be caused by a hiatus hernia, gastroesophageal reflux, gastric retention or abnormally slow stomach emptying of food ingested before bedtime, certain medications like aspirin or Advil which can irritate the stomach lining or by intolerance to certain oily foods. Try not eating anything after supper. See a gastroenterologist as needed