What is the breed?
For how long has she been like this?
Does she eat any non food items such as bones, rawhides, pig ears, greenies, grass, sticks, etc.?
Does she eat any human food , if so what?
Could she have gotten into a toxin or garbage?
Thank you for that information. If they got into the garbage there could be a few things going on. An obstruction from a non food item, garbage toxicosis, or pancreatitis from fatty food that she found in the garbage.
In any event all require vet attention especially since this has been going on since Monday. Small pups can dehydrate very quickly from vomiting so this may be why she is shaky.
I would not hesitate to seek vet care and in the mean time look at her gums and make sure they are not pale or white, this would need immediate attention. Take her temp rectally to make sure that is normal. Normal for dogs is 100.5 to 102.5.
Here is more on the illnesses I have mentioned. the sites will tell you symptoms and treatments, but I would be calling your vet at this point.
Obstruction (foreign body)
Garbage gut http://www.petplace.com/dogs/garbage-toxicosis-garbage-gut/page1.aspx