Vomiting and pooping

So in the past month I've been having these episodes where I get the runs really bad and start throwing up. It happens out of no where I'll just wake up one morning feeling sick. Its happened 3 times this month already each time the night before i ate something different i cant think of anything I had in common those days. I forsure not pregnant ive taken pregnancy test it was negative and I just ended my period. Has this happened to anyone? If so what was causing it for you?