Projectile vomiting in two year old child?

I have a two year old daughter who has just gotten over her first "run in" with the stomach flu. It really hit her hard, since this was her first time. She was finally symptom free on tuesday of this week and was able to return to day care. Now every night either just before bed, or shortly after she goes to bed for a couple hours she wakes up and projectile vomits. The "composition" is usually made up of what she had for supper. We have tried the "BRAT" diet last night and tonight thinking maybe this was just maybe one final stage of the flu virus completely getting out of her system. Tonight she ate about 2 bananas and a few bites of yogurt. At approximately nine thirty tonight she went to lay down and then immediately came out of her room came to the door and opened her mouth and out everything came again tonight. Most of this comprised of bites of undigested banana and the water and juice that she had drank since she came home from day care today. My wife and I are at our wits end, I have not slept a full night in over a week now, and have missed all of my cles that I am taking in night school this week. I am planning on taking her to the doctor in the morning. Any advice as to what to ask the doctor, or if any of you parents out there can help us please send us any advice on what is going on. I am now worried that she will start to become malnourished, and worst yet dehydrated. Please help us get going the right direction. Thank you in advance for any help anyone can provide.