I'm sooo sorry for your loss.
I hope you all feel better soon. Just for a FYI for new breeders, I would never use frontline or any other chemical on a pregnant dog. Vets and pharmacy Co's can say it's safe but you just never know. I used Bio Spot on a 100 lb dog of mine and he has a VERY bad nervous system reaction and so did the 40 lb mix I gave at the same time. Butch shook and couldn't walk at all for 2 days. Hershey couldn't lift her tail for about 1 wk. 99% of dogs I'm sure it's fine but in mine it was not. It is supposed to stay in the skin and not go into the blood stream but it sure did on my dogs. Who knows if the frontline was responsible but that could have been a factor. I just read on my frontline box it is safe in breeding, pregnant and lactating bitches. I just don't take that chance. We all just do the best we can and it sounds like you are a wonderful pet owner and did all you could.