Im also in NC and work with rescue alot.
Have you noticed if your cat appears to still have a large or distended belly?
How many kittens did she have?
Did she feed them and attend to them normally until yesterday?
How long after the kittens was born did she show symptoms of illness?
Did ALL the kittens die the same day?
Did you notice she was nursing them frequently?
She may have not delivered ALL the unborn kittens which is very painful and fatal if not found and handled by a vet.
If you need help finding a charity group to help you please email me.