Forever is a potentially very long time, Seamuslee, but it is indeed possible to maintain your self-awareness straight through your night's sleep. It is not easy, and can take a lifetime to master, but some have done it, or at least tasted it a few times -- even some folks here at DV, should we accept their claims.

So it is hard, but not "too hard," I think; provided your mind is in the right place. To start getting it there, I suggest you look into a discipline called dream yoga, and maybe even check out Sivason's DVA class on the subject. Dream yoga is the first step toward sleep yoga which, if mastered, offers you an opportunity to maintain self-awareness forever -- even after death.

Good luck pursuing this excellent and, yes, difficult goal!