thought I heard a knock

Was asleep with the cats. No radio, no music. Jerked my head up for I thought I heard a knock. I despise door knockers, particularly unannounced door knockers.
Why? What do you fear?
Have an image of an old ice cream man; wrinkled face; dressed all in white with a black bow tie; he carries a large net with a long pole handle.
Dog catcher?
So I crept to the window, moved the blinds askew to see who might be on the porch- no one there. Back to bed, laying there with that resounding knocking, playing over and over, and my heart racing..
It's ok. Maybe the wind blew, tapped a tree against the house.
There's no reason for anyone to knock on my door. I've paid my taxes. All communication is done by wire. My intimacy is with animals. My avoidance serves as repellent, and works very well.
So don't worry. No one will come. Just sleep now. Everything is ok.
The wind blew, tapped a tree against the house. Ok?