A sensation of vomiting is associated with three causes, either in isolation or in combination. a)increased gastric secretion over night b)A pronounced gag reflex c)Increased anxiety. Treatment- a)have at least 1-2 glasses of water as soon as you get up. b)avoid taking heavy , fatty ,oily food in dinner. c)avoid aggressive cleaning of the back of the tongue. If the above treatment doesnot help , one may need a course of antacids. Hope this helps. Regards.