J.W.
I was your daughter. The best advice I can give you is to give her some control of what she eats and doesn't. My pediatrician told my mother as long as I am eating carbs, protein, and fats each day then I wasn't going to suffer from malnutrition. One summer all I ate was strawberries and hotdogs. Now my mom did make me take a chewable vitamin and I drank milk with most of my meals so there were some other nutrients going on, but for me having control of what I ate was a very big deal. I am still very fickle but healthy. Try taking her to the store and let her pick out something for breakfast, lunch, dinner. Maybe let her make a menu using pictures. Get some cooking magazines (kraft is one of my free favorites) and just let her pick some things to eat. Don't worry about the nutrition of it at first. Just get her eating again. Then you can expand variety and brand.
I suffered from chronic stomach flu, and anything I threw up I never ate again. There is something maybe your sense of smell that keeps you from being able to control your gag reflex to those foods. Don't dismiss her aversions. Charlotte Mason, an education philosopher made an apt point of saying food that it is eaten must be done with enjoyment otherwise the body doesn't absorb the nutrients. Now it isn't completely true that you won't absorb any nutrients but there is truth that high acidity in the stomach can dissolve nutrients before they are absorbed. I think if you give her a little control you may find that her fear of getting sick again resolves. Also teach her to wash her foods and hands, that is empowering to know where germs come from and how to get rid of them.