Hi slip dear!
I've heard a voice like that once before too, and it might come from your subconcious mind... surfacing, or from some outside entity...from a time/space rift...aliens or spirits...nobody really knows what causes these unexplicable events, but many people experience them.

My father was a Lt. Col in the Marines (suffice it to say he was not the type to get all carried away by silly imaginings) and when we lived in Hawaii he woke up to the sight of a woman in a long white nightgown crossing the room. He thought it was his wife at first, but Lanelle was sleeping beside him. He turned on the lights and woke her up and told her about it. So weird.
I slept downstairs, and one night, months after this, I was drifting off to sleep when I heard what sounded like someone sweeping with a broom outside my closed bedroom door. I called out to see if it was my stepmother, but no one responded. Then there was a little push on my door, just enough to notice, and then silence. This pattern went on for SEVERAL HOURS while I watched. Talk about freaked out! After that night, it never happened again.

I have had many strange and unexplainable events like that in my life, but I don't think I am crazy. Many sensitivities are set off by stress, and I know you have had a lot of that lately, so don't add worry about this to your plate. Unless voices tell you to hurt yourself or others, it's not a problem.

I personally think there are various levels of experience beyond the everyday one we live in-