If she's allergic to the anesthetic it should clear up in a day or two. As far as pain goes at my work (I'm a CVT) every animal that undergoes general anethesia gets an injection for pain that lasts 24 hours for dogs or 48 for cats. It doesn't matter if it's a spay, neuter, dental, mass removal they all get it (well unless they have liver failure or something but then we probably would use something else).
You can try giving your dog Famotidine (aka: pepsid) and see if that helps calm her stomach down but I wouldn't feed her until she stops vomiting. We usually recommend pet owners only give their animals small amounts of food and water at night after the surgery and if they don't eats thats fine too but most animals should be back to normal the day after surgery.