Here is a recipe for an electrolyte mix that you can give her:
1 cup hot water
2 tsp sugar
1/8 tsp salt
1/8 tsp baking soda
Mix together to dissolve. Let cool.
Add 1 tsp of mixture to a gallon of cold water
She's probably just weak, so make sure she drinks that. Also, a lot of people on the forums here give their chicks a mixture of chick starter and yogurt, so you could try that. You can put her with a stuffed animal, or you can give her another small, CALM chick. If the area is red, a red light will stop the other chicks from picking at it.
Make sure that she's warm enough, but not too warm.
We had polish before and we ended up giving them much more attention than the others. I remember that mine were very small compared to the others.
Also, remember to check for pasty butt. It can cause death, but probably won't be much of a worry for you since she's a couple days old. But be sure to check periodically!
I hope that helps, and good luck with her!
Chelsea