i get this too. i think that its because theres nothing in my small intestine at night so the bile backs up through the pyloric sphincter (the circular muscle that closes the stomach off from the small intestine), causing me to puke the bile. unfortunately, i havent found a solution to it yet. you might try having a meal juste before going to bed, or keeping a snack by your bed in case you wake up hungry during the night (though i dont usually wake up until after the horrible nausea sets in). otherwise, just try talking to a gastroenterologist.
have you ever had your gallbladder checked? Do you have any yellow tones in your eyes or skin?