[WinstonMom]

First of all, I am sorry for your loss, try not to feel guilty about it, it is not your fault, sadly these things happen.
How big is your whelping box, maybe your mama is having a hard time finding enough room to lay down without laying on one of her babies. I use a clear plastic tote, one of the ones that are designed to store stuff under the bed, they are high enough to keep the babies in and still have easy access for mama. The one I use is about 18 x 24 inches, it gives mama enough room to stretch out and still lots of room for the babes. I also like the clear plastic as you can see through it and see if a pup gets behind mama. I use a washable pee pad cut to fit for my bedding, nothing too thick or with too many layers for pups to get tangled in. These totes are big enough that I can put my heating pad under one side and leave the other side cooler for mama. Your pups will instinctively crawl to the heated side or to their mama. I would rather my box looks a little one the big side, than too small for everyone to be comfortable.