My pomeranean dog has had 2 lits. Now and they both keep dying about three days after birth. She cleans and feeds them but for some reason at night time she gets really stressed and that's when they usually either dye or she eats them.

I'd stop breading the dog first of all, and second, when new puppies are born I'd have a vet see them and the mother dog immediately.

Definitely need a lot more info here.

Where is the whelping box being kept?
How old is the b*tch?

B*tches will kill and often eat their puppies for a number of reasons, illness, stress, no maternal instinct, the list goes on.

2 litters is more than enough to put her through, I would highly suggest spaying at this point, something is obviously amiss.

It could be a multitude of things, could be a psychological problem with the B***h it could be a genetic or inherited problem with the pups, or even the dam, it could be a genetic or inherited defect from the sire's side of the family.
A responsible breeder would realize breeding dogs is not 100% safe, things do and can and will happen. Everything from mastitis to losing pups or even the mother. Please stop breeding your dog, she doesn't deserve it, emotionally or physically. And please get her fixed. Also, maybe you should take any remaining pups and the dam to the vet immediately.

I don't have much to add here, either then I think it's time to get her spayed. 2 litters and she has killed them both off is sure sign she is not meant to breed. Do you have a breeding mentor, or had both sire and b!tch tested for genetic defects before breeding?