Hole in the wall

A very odd thing just happened. I was upstairs, hanging up the washing, when I heard an almighty crash from somewhere. After investigation, I found that the mirror that I had put on the wall in my downstairs loo over a year ago (and was very proud of having managed to do myself), had decided to jump off and take a chunk out of the wall! The screws are still firmly in the wall, so I cannot begin to work out why it has suddenly fallen off. Poltergeist? Boredom? Who knows. I'm now rather worried about putting it back again. And quite what to do about the hole. Any suggestions on how it could be repaired?

A busy day today. After spending a lot of it on Skype and the phone, I have chosen and ordered vinyl flooring for the kitchen (only a year or so after the kitchen was finished, but who's counting), washed the car, and then took up the laminate flooring in my hall which was a lot easier than I had thought it might be. Good to know that the floor underneath it is in good condition, ready for the vinyl to be laid in a few weeks' time. Can't wait! And for me, that was pretty speedy decision making. Go me!