So, moral of the story is: don't listen to people who say not to get a case for your phone. I don't know if it would have prevented the glass from breaking, but it couldn't have hurt.
The way it landed, right on the corner, is probably why it caused so much damage.
I feel sick right now. This will be my last iPhone. I am not going to be paying this amount of money for something that can be broken so easily.