My tiny little poodle/chihuahua has been up all night quivering, like she does sometimes, but this is totally out of the ordinary. She wants to be by herself which she NEVER does, and literally hasn't slept a wink which she NEVER does. She did have her rabies shots and stuff yesterday, could that be making her sick?

PLEASE help me! Is something wrong with her?

Its very likely that she is having a reaction to her vaccines. With little dogs, getting the rabies vax and the combo vax at the same time can overload their little bodies.

You need to call your vet back and let them know that she is having a reaction and she is sick. They can help you.