What Causes Vomiting, Abdominal Cramps, Fever, Chills And Insomnia?

Beginning shortly after 7 am CST and continuing to this moment, my 68 yr old husband is vomiting and experiencing cramping in his abdomen. Vomit is green in color, no food intake since 8 or 9 p.m. Saturday night, and only 1/2 cup of coffee w/french vanilla creamer upon awaking at 7 a.m. Intermittent fever and chills, unable to sleep more than 5-10 mins. at a time. Pouring sweat one minute and freezing the next along with claminess and cold skin the next. Nine hours and counting...this has happend at least 7 times before and hospital tests revealed nothing, Please help!