Questions in Grief

A week ago I lost a best friend. Out of nowhere, she got sick and died a week later. She had a 10 month old baby, and now her widowed husband is left without the love of his life, and left with another human to raise.  My friend knew that colon cancer ran in her family so a few months prior to her getting sick, she had a voulentary colonectamy. Cancer got her anyway. My heart is broken from the loss of a lifelong bestfriend. She lived down the street from me, so I spent nearly everyday either playing, studying, gossiping, or watching MTV at her house (because my dad blocked that channel). 
I can't help but wonder why the hell she has to die, and I get to live. Don't misunderstand, I want to live, but I have flirted with so much dangerous behavior pertaining to my ED that I almost feel like I have nine lives. She did everything right, even taking extra precautions to make sure she satyed around fro her daughter, and she's not here and I am.  It doesn't make since, but I am strating to realize two really major things: 1. Life is so fucking fradgile, and 2. There has to be a significant reason I am still here. I was told in the hospital that the doctors had never seen anyone survive with levels that low, but I did. Twice. Why? Like, really, WHY? 
I'm crushed from the loss of the most authintic friend, and I am greatful for the chance to start living more and more each day. This is not dumb luck.