Chronic nausea and vomiting for almost 4 years!

My name is Melissa and im 21 years old. I got sick in '09 after drinking the barium smoothie for an abdominal CT scan, idk whether it's related or not, but i figured i should include everything i can. I've been through 2 general practitioners, 2 gastroenterologist's, 2 ENT'S, 1 cardiologist, and 1 psychiatrist. My heart is fine, i have Virtigo, but my inner ear is structurally normal, i have gastritis and a tiny hiatus hernia, but i would assume that's from all the throwing up. I also have depression and anxiety.
It's usually worst in the morning. It almost always wakes me up and sends me to the bathroom, vomiting doesn't bring any relief and most of the time there isn't even anything in my system so I'm just dry-heaving.
I wont be able to keep any food down, not even water sometimes for days on end.
an injection of Zofran helps a little bit, but nothing makes it go away.
I've been prescribed almost every antiemic on the market and they don't help at all.
I've started to really lose weight, I'm under 100 lbs now and getting really scared.
Even when im not throwing up, the nausea is still always there, I don't remember what it feels like to not be nauseous anymore..