My puppy has had bad experiences and i need help before its too late!?

My dog (shitzu) had 4 gawjus puppies 3 weeks ago and recently a brown one, sooki, has fallen off the bed 2 times, due to wrigling and exploring. After that she has been having nightmares and is always crying. Its not because shes in pain. Its becoz of her mind that keeps reminding her of that experience. It makes me depressed when i hear or see her crying or having horrid nightmares. Is there any possible way i could stop it?