F.X.
If she has dry heaves, her stomach needs to heal so you need to just keep her hydrated and not worry about food right now. Think about things that have fluid in them, like popsicles and jello. The sugar is actually good for her right now, my mom always says (like when she is ready to try a few bites of food, after she can keep down a few bites of crackers, my mom always suggests a bit of jelly on toast or crackers for the sugar her body needs-- I guess it's a blood sugar thing? Not sure) My son was really sick with a stomach bug once and we took him to the doctor because it was going on for days-- at first he said don't worry about the BRAT diet and just try and get him to keep ANYTHING down, but it got worse so I took him back-- the doctor we saw the second time said you can't just feed them "anything" because certain foods like dairy and fatty foods will make it worse until the tummy heals for a couple of days... so once she is able to keep down fluids for nearly a whole day, you can start trying foods like toast, crackers, bananas, plain pasta, bananas, dry cereal, watermelon...
By the way, whatever you are giving her to drink, try feeding it to her on a spoon in little sips, or use one of those little cups that come with medicine so she is only take a sip at a time