Everything Karla said, and one other thing - a tight bloated tummy can be a sign of stomach torsion which can kill very quickly. PLEASE get your dog to a vet ASAP!
Hiding in the closet & shaking is a sign of extreme pain......
You need to call your Vet and see if he/she does a payment plan...If not, call around and find one that does!
The swollen stomach w/ vomit could be an obstruction....Do you see anything like a toy, bone, chew, sock, etc., that is half eaten, in the house? A blockage left untreated will cause death shortly.....
The tight stomach can also be a indicator of a back injury....Is she a jumper off of furniture? A back injury is common in tiny dogs.....Pain medication from your Vet & crate rest is a must for a back problem....
Either way, you have to find a way to get the money to get her to a doctor....She is suffering and does not know why...This is your responsibility as a pet owner....
Do you have anything, like your computer, that you could go pawn to get money to help her? Do you have anyone that can loan you some money & you pay them back?
There is nothing you can do for her at home......She needs help!
You might try calling your local Humane Society and turn her over to them....They will provide the treatment she needs and then put her up for adoption to someone that can afford her medical needs!....Although this sounds harsh, it would be in her best interest.....
Either way, she needs a doctor and to do nothing is considered neglect......I hope you find a way to help her.......Karla