I was running away from some sort of zombie monster that was eating my friends, or at least the people who were running with me, in a school. One by one, my friends would disappear only to be discovered dead in some way (decapitated, maimed, gnawed on, etc.). At the end, when all that was left was me, I discovered I was the monster I was running from. I killed/maimed/ate my friends. Lovely.
And, to complete that experience, I awake to my friend's pics of a Zombie Walk.