Sometimes I think dogs have too good a memory. My bulldog Wilson is also fearful of a lot of things. When he was a puppy he accidentally tipped a food tray onto himself. He's been afraid of things overhead since then. I can't put on my ceiling fan anymore cause it scares him to death. If I carry anything large like boxes, big bags, brooms well most anything larger than himself he runs and hides. He's a great big bulldog 60+lbs yet he scares easily. Doesn't bark at anybody though and not afraid of other dogs. Sorry, don't have any advice but at least you know there are other dogs with this unusual fear.