Why do i gag and sometimes even vomit when brushing my teeth? this makes oral hygiene difficult as i may have to wait until pm to brush w/o nausea.

Not uncommon: Many people have similar problems. I usually advise people to try a smaller head toothbrush, a child head, or compact head. Always use a soft brush. Maybe change toothpaste, as the flavor in some can elicit a gag reflex. Maneuver your jaw to different positions for help. At least rinse with water after sweet drinks or sweet foods to limit the acid attack that occurs after sugar is consumed.