question: after eating a meal  in a in a restaurant I suddenly  started to get severe back pain and felt faint and weak the pain got worse I could not stand up alone my legs went like jelly, then I vomited, the I felt much better but I am still getting some back pain and my stomach  is queasy this all started  last evening. could it be something I have eater ?. I must say I have never felt so ill so quickly,