While I am, of course, not a Dr...I will say that this happened to me often before I had surgery. I was a teacher & if I were standing talking to other teachers, like at recess, it always happened - I'd just stumble backwards like a drunk person. I'd always say "Oh, I have horrible balance!" I was told by the Dr.'s that (if you hadnt been drinking
), this was a huge sign that there was SOMETHING "extra" in your head. In fact, when people ask me what I might tell others to look for, my standard response is, "If you are in a group of people and someone who hasn't been drinking stumbles back, you should ask them how often this happens. I don't want to be paranoid but if it happens frequently, they need to get it checked out."
It might not be an AN, but you probably need to get it checked!