Cat had kittens 2 days ago, and she just gave birth to another one this morning&it was dead w/no afterbirth?!?

My mothers cat myrtle had 4 kittens 2 days ago, and this morning she had another one...ate the sack...and it was dead. She didn't chew the cord...just left it hanging so they cut it. Problem is she didn't give birth to no afterbirth. Is this normal? When we feel on her stomach it feels like there is another baby in there. Plz help no money for vet.