Stomach flu???????????????

my 4 year old sister was sick for about 3 days. during that time period she threw up about 3 or 4 times at night and had diarrhea just once. the docter said it was something that was going around and that she will be fine.she is fine today but today me and my 13 yr old brother woke up vomiting. i only vomited once while he vomited 3 times with diarrhea. i haven't vomited for about 6 hrs now but i still feel nauseous (btw i didnt get diarrhea)i dont feel like eating at all, im afraid i will just throw it up because of my nausea. i have been drinking water though, little by little.does this sound like the stomach flu? is it just a mild case? how long do stomach flus usually last? someone help please