C.K.
Hmmm. Given the lack of fever and your daughter bouncing back quite quickly, I am wondering if it's a food allergy or sensitivity? They can crop up at anytime, even if a person was previously able to tolerate the food.
For example, my son can sometimes tolerate dairy products just fine, and sometimes he screams and then vomits. (He's 1, so he can't vocalize yet as to what's hurting.) After a couple of episodes like that, we pulled him off dairy and started giving him goat's milk, and he's been fine.
I would say maybe keep a food diary for a few months and see if you notice any connections. I would also keep track of any other digestion issues she might have, like a sore stomach or constipation or diarrhea.
In any event, the flora and fauna in her stomach may be off kilter from all the vomiting. I would recommend giving her yogurt or kefir with *live active cultures* to restore the good bacteria in her digestive track. I know you can also get active cultures in pill form, but I've never done it myself.
Good luck!