Hello. I'm Dr. Christensen.
I am so sorry for your loss.
It isn't clear from the information you've furnished whether or not an autopsy will be performed, but this might help answer some of your questions. Unfortunately, though, even an autopsy may not fill in all the gaps if your baby died from sudden infant death syndrome
(SIDS). Her appearance when you discovered her is not unusual for SIDS: the blue coloration in her dependent areas (her downward body parts) and paleness on her upper body parts are simply the result of gravity, which pulls blood downward when it stops circulating. This is called "pooling" or "dependent rubor." And studies suggest that about 15% of SIDS deaths are associated with bleeding from the baby's mouth or nose. (Such bleeding can also be associated with suffocation or with trauma to the soft tissues of the mouth, which might occur during a seizure
I suggest you try again to get your physician's thoughts on what happened to your baby, as this will help you work through this extremely painful time. You and your husband would probably benefit from grief counseling, too, so ask your doctor for a referral.
My best to you.