Meditation during Sleep

Yesterday (Friday 22/1/10) was weird. When I woke up it was as though I had not slept throughout the night. The dream state and waking state have become indistinguishable, but yet I remembered what happened. It was the first time I had meditated during the sleeping state. Or maybe, it was a state where I was neither fully awake (in the normal sense) nor completely in a deep sleep state. What happened was that I had done only 5 sessions of my guru yoga. And there is one more to go. And I thought I could do it one more time after I did my Vajrasattva long mantras 30 times. I usually recite those mantras lying down as my consciousness slowly go to sleep (the purpose being to purify everything as I enter sleep). But somehow, I ended up sleeping. Maybe, subconsciously I knew I had one more meditation session to go and it just slipped into the meditation mode even though physically I may be sleeping. I could say that because I remembered I did all the meditation and the visualisations were clear, because I was not fully in a deep sleep state, I also knew I was sleeping physically. If you don't understand what I am saying, I don't blame you. It's weird to say the least... it was weirder than the 2 times (I think) when I woke up and found out that I was still reciting the mantra I was reciting at the time when I slept. But I am happy ...at least, it's an indication it shows that the imprint from doing the guru yoga meditation is getting stronger. It must be strong enough so that I can do it even in the bardo state. Eventually I hope to be able to do dream yoga.