Descartes and dreams

I think I've been studying too much philosophy and Descartes, it is beginning to mess with my dreams.

I was asleep in a dream, when I suddenly recalled my lecturer asking us how we know whether we are awake in reality or asleep in a dream when we are seemingly awake in both cases, dreams and reality. I asked myself while in the dream, am I dreaming or am I awake? And somehow, I came to the conclusion in my dreams that I was really awake when I was actually asleep.