I am actually the father, my wife is gone for the day so i was doing laundry and cleaning so she could come home to a neat house.
My husband takes care of our little one 3 days a week, and the 4th day she was standing on her own holding onto stuff, he had her on the hardwood floor standing at the bed, and she fell over and smacked her head on the floor.
He called in a panic, thinking she'd have a concussion, but she just had a minor bruise. He felt awful. She was acting fine shortly after...
I guess as long as they're acting normal right after you dont' have anything to worry about (except making sure it doesn't happen again, because it's so hard on one's heart when it does!)
Enjoy the rest of your day.