Eating, even one pack of plain crisp, will cause sickness. This is why you threw up. The Epsom Salt mixture (assuming you did the Hulda liver flush) opens up every canalisation into your gut and, food of any type will cause trouble most likely letting too much bile out at once and urging your metabolism to expell all the junk. Well the important is that you were still succesfull in helping stones out.
I will always remember on the second run of 3 liver flushes, when my smell came back. It was so amazing to gain my sense of smell back. Everywhere I went, was a new experience. I was in complete awe.