I'm so sorry about your puppy's death and your painful memory of seeing her dead body. It's important now that you substitute that tragic image with a happy one. It's time to celebrate your pup's life and remember the good moments.
Hopefully, you have photos of your dog. Choose a favorite one and go to the store and select a beautiful frame for it. Put it on the nightstand next to your bed or someplace where you'll see it each day. Eventually, your sad vision of your dog will be replaced by this happier one.
If you don't have a photo of her, paint a picture or make a drawing of your pup. Depict her doing something she loved: chewing a bone, playing fetch, running through the grass, or cuddling with you.
Give yourself some time, patience, and loving care. What you're experiencing is normal.