Some lucid dreamers do end up in a dark empty void. Sometimes it's a place, where dream wants to show you something of importance, that's why there are no distractions, only a couple of items you should be concentrating on. I'm not sure, if this is your case, also. Did you try to yell out "is there something important you want to show me?".

Or, did you try to get out of there by teleporting someplace else?