circumvacuity
Circumvacuity is the odd feeling you get when you're walking along and you come to an intersection where a car is waiting to turn, and just as you walk around the rear of the car, it leaves, and you find yourself walking around ... nothing.
I got a terrible case of circumvacuity at the intersection of Main Street and High, today; so bad, in fact, that I had trouble walking a straight line.