Oh Aly, I understand very well some of the feelings you are feeling right now. One day back in 1996 I went off to work thinking all was well in my household. When I came home that night my beloved Whitney (8 yr. old standard poodle) was dead on my sofa. :( The vet assumed it was a heart attack since she had been just fine, but offered to do an autopsy. I declined because I couldn't bear to do that to her. Sometimes I wish I had though because I have such guilt about her death, especially since I was not with her at the time she died and never had a clue that anything was wrong. An autopsy might help to answer some of your questions but of course it is something you would need to feel comfortable with. (((hugs)))