I am the first to recommend treating at home, but your description is somewhat alarming: Â "Pale, hollow eyes, crying in thirst". Â 3 days of vomiting is a long time for a little one, well for anyone, and this makes me feel very concerned. Â As I am sure most already know, dehydration can become life-threatening very quickly, so it is good you are noting her appearance. Â
This may sound strange, but how does her breath smell? Â Obviously all the vomiting she has done will make her breath smell bad, but it is good to check her breath as she exhales. Â Some people can detect the off smell when a person or animal begins to suffer damage from dehydration or liver problems caused by dehydration. Â If she has an unusual "sicky-sweet alcohol" odor to her breath, I would immediately take her in.
If she hasn't had diarrhea, an enema should help hydrate her. Â I have never used the garlic enemas before so can't give a thumbs up or down from personal experience... Â Whatever enema you do, make sure you keep her calm and quiet as you do it, because you don't want her expending energy fighting the procedure - and you don't want her to strain and loose the water... Â
If she doesn't show an almost immediate improvement in her appearance, I would really consider taking her in for IV fluids. Â It is also possible to give fluids at home, but unless you have seen it done and feel confident, it is not a good idea. Â
Also, in the meanwhile, if you aren't already... Â To help soothe her mouth and make her feel less thirsty, I would give her ice to suck on. Â She really needs electrolytes, so frozen pedialyte would be better than plain ice. Â (You can also make your own electrolyte drink, but don't have the recipe handy at the moment -- will look it up and post in a few minutes if I can find it.)