Sorry it's been so long with no reply. Yes! I have had this many times. I call it the "Half-dream" for lack of better term. It is just one step away from entering a full on lucid dream. I'm surprised you went 50 minutes like this. I suspect you must have entered a full lucid without realizing it. When I get this I usually just do stabilizing techniques or mildly interact with the dream environment until it becomes more and more "real". Then I do my lucid goals. That's really great you got to this stage keep it up.