Is it normal for a puppy to shake when its asleep and look like its having a fit?

i got a puppy yesterday, shes 7weeks old, a few times when shes been asleep she will start shaking really fast, her whole body, i clapped my and yesterday next to her when she did this and she jumped up.... didnt mean to scare her just wanted to see if she could stop. and she did. is she just dreaming when she shakes?