I am worried about my symptoms. I have been feeling queasy off and on for a week. The about 2 days ago I ate?

something I wouldn not normally eat from a restaurant, then I took some multivitamins. I got extremely nauseated and threw up and very cold clammy skin.. The ER said I probably had a reaction to the food or vitamins, They also said I had a slightly high white cell count. My question is this, 2 days later I do not feel right, my stomach is weak , queasy and strange. What could I have? I am worried I have something they didn't see.. I am taking an antibiotic, but I am scared about stomach cancer, ovarian cancer and all kinds of things ! I know I"m too focued on it, but what could I have?