Bless your heart....I know you feel terrible but that can happen in a blink of an eye and so far it sounds like you were lucky ....You could have fallen ON her or she could have hit headfirst...it could have been so much worse...but any accident is very tramautizing....and I feel so bad for both of you....
I truly hope she is going to be ok .....That had to be awful and you did the right thing going straight to the vet...you are NOT a bad mom....you just had an accident and they happen to us ALL.....
IF there is a 24 hour hospital nearby you may want that phone number handy....and you can always call someone to see what to look for...or someone here can help you....
Hang in there and lots of well wishes for your baby...Please let us know how she is ?