I'm fairly certain it was a stroke...I don't know where you guys heard that it wasn't, but on the news 2 days ago they said it was a stroke.
She didn't have a stroke, she posted on twitter that she was fine :D so we can all laugh and be happy.
I don't know about what you guys may have heard, but as far as I know when you have a stroke while standing up, chances are that you're going to drop to the floor like a tonne of bricks