I know from my own experiances that once you start to feel n* and you have emet...it is very impossible to calm down and feel better...sometimes i try reading a book, taking a bath or playing a video game or something. anything to try to distract my mind..of course it doesnt always work, but give it a shot...you will be ok ... its most likely just stress...even if you dont feel stressed at the particular moment it happened, it could still be related to something in the back of your mind. take a deep breath!! I hope you feel better hun!!!