This could be a medical issue. How much water are you giving her when you fill her bowl? My immediate suggestion would be to give her some Pedialyte (fluid replacement- sold in the pediactric section of your grocery store or your pharmacy). She is dehydrated from vomiting...she could be drinking the water to rid her system of something- has she gotten into any poision, cleaning supplies, etc lately? Have you seen her eating ribbon, twine, plastic? it could be an intestional blockage also....the best option, is to take her to an after hours emergency vet to determine the cause of her vomiting. Keep her hydrated on the way up there by giving her pedialyte and keeping her warm. Also, I know this is a gross question, but what did her vomit look like? Was there a lot each time she threw up??? These are questions your vet should ask you. When you get her there, ask your vet to give her a Sub Q iv to hydrate her. It sounds like she is quite dehydrated. Dehydration in felines can rapidly cause other issues...please have her checked out ASAP. My prayers are with you. Please feel free to pm me if you need anything else!