Sudden death of 6 week puppy

We brought our Siberian Husky puppy home saturday 11/8/08. she was 6 weeks old, and i had her picked out from the breeder since she was 1 week old. she was great the frist night home with us. she had diareha which the breeder said was caused by the vaccinations she had received the day before coming home. no blood in the stool and no vomiting. she did have a slight "hacking" at one moment in the 2days home but other then that she was great. pottied outside, ate, and drank fine! played really good! this morning 11/10/08 we woke up to take her outside and we discovered her curled up "sleeping" in the corner of her crate. she usually comes running to the door to be let out. instead she was still laying there. i knew something was wrong. i said her name and still laid there. i stared at her in disbelief that she was dead. until i realized she was NOT breathin and i grabbed her and she was stiff. i screamed for my boyfriend who then came running to find that i was sitting next to our dead 6 week old puppy who we had only had home for 2 days. she had no signs of illness, or anything. My first thought was "omg, she got too cold or too lonely or barked and barked but we didnt hear her from our room" ...i didnt know what to do. we cried and cried and cried. until we finally pulled it together and called a nearby vet. we took her there to get an autopsy and what they found was iflamation of the lungs. but then couldnt further examine her so the tests were being sent outside our town. so we paid for all of it to get done in hopes of getting some answers. i was hopeing maybe someone could share some similar experiences to enlighten us. i feel like "we are horrible parents" to our new puppy.i loved her so much and now shes gone. not to mention she loved us, including my 1yr old daughter. ive researched and researched things to try to come to some conclusions, but i just dont know. the night we brought her home we did have our whoel family over to eat dinner and greet the puppy. could all he interaction from everyone made her sick kind of like a newborns immune system could the puppies immune system be weak enough to die from germs on all of their hands?? any feedback would be great. it would help mend my heart and understand that its not our fault but it just happens.
   
i miss her so much

I am so sorry that is beyond terrible. But you are not bad parents!
   
No one got your puppy sick. Your puppy had what it had before you got her. You had her for 2 days and a little diarrhea and 1 hack was not enough to alarm anyone. Even if you had gotten up in the middle of the night and noticed something was wrong and brought her to an emergency vet I doubt that they could have saved her. It happened way too quick. She may have been born with it. It used to be that puppies had to be at least 8 weeks before they were weaned and now it seems that breeders are just booting them out. I personally think that 6 weeks is too soon. I have met people who got puppies as soon as 4 weeks old. It is just wrong.

so do you recommend that when getting a puppy it be 8-10weeks. the pups werent with their mother any longer anways. the breeder had them seperated and on puppy food at the time we picked her up.