After updating to 5.1, phone wont get past black "Google" screen

Last night I upgraded to 5.1 via the built-in update functionality. This phone is not rooted.

Well, now my phone won't get past the black screen with the white "Google" logo when I try and boot it up. I can get into fastboot mode though.

However, fastboot is not showing the phone as a device in windows, so I can't just re-flash the stock 5.1 android rom.

Also, when I try and go into recovery mode I get an android icon with a red exclamation point in a triangle that says "No command."

Is my phone screwed?