Disturbing Dreams?

I rarely dream and when I do it's either something ridiculus (ex., I once had a dream in which I was teaching a gymnasium full of monkeys how to squaredance) or seems frighteningly real but is not relevent to my life in anyway. These "real" dreams are disturbingly vivid and lack the flaws or absurdities of "normal" dreams. In them I am always someone else and it feels as if I am living someone else's life or reliving their memories. I've had these type of dreams my whole life and have had many dreams that have been reoccuring over the course of several years. I've never given them much mind, but there starting to creep me out. Any explinations or theories would be appreciated. Thx