Mystery Solved!

So I spent several periods on Thursday wondering why my shoe felt so loose, almost as if I was going to walk right out of it and leave it behind me on the floor . . . I wondered if my right foot had shrunk or if my plantar fasciitis insert was to blame . . . but then-- after a good two hours of this nonsense-- I had the bright idea to actually lift my pant leg up and look at the shoe, and-- wonder of wonders-- it was untied.