If she throws up the water, you definitely have an emergency situation, as a dog, especially a dog
her age can dehydrate very fast. Don't worry about her not eating
for now. Her system wouldn't be able to cope with food.
I can't tell you what is wrong with her, but it could be many things including Parvo, pancreatitis, havng eaten something which has violently disagreed with her, or something toxic for dogs, or it may be just a bad tummy-bug that has got a bit out of hand.