lights out

I blacked out yesterday afternoon. I was having a lie down at home and got out of bed too quickly. It's never happened to me before. When I awoke, I found myself lying on the floor and the dog was staring at me from the bed. I had a bit of pain on the right side of my body (I think I must have hit the side of the bed on my way down) and I scraped my elbow. Nothing major...luckily I didn't hit my head. Hmmm....things certainly aren't the same as when I was younger.