My sister has this thing where she gets herself all worked up for events and then doesnt want to go for some stupid reason. I need help because my mum has bought the dress, bag, earings the works and now she doesnt want to go to her formul. She has this thing where she cant eat infront of friends she has to be with a family member. So she feels sick and tells her self shes going to vomit. And no she is not anorexic or anything like that. She has exercises to get over this problem but its not working. Please help i really want her to go.