Your earthly senses slowly regain function as you feel yourself sliding through something warm and moist, finally greeted by the relative cold as you leave this place. You try to see where you are, but you cannot as you seem to be blind, your limbs feel weird and you even seem to have a third leg near your butt...
After some time. you slowly start to gain sight, although only in shades of gray. You finally get the chance to take a look at where you are: you seem to have tiny clawed paws, your body is completely hairy, and trying to speak only reveals high-pitched barks. Add to that the pups that are lying next to you, against a mother dog that seems huge compared to you, and the whole thing clicks on what you are.
You have been reincarnated as a dog, and you have crossed the barrier of birth into being a healthy pup.