Toms can be very finicky. Not sure how long your blind had been set up prior to your hunting it, but that may have spooked him if it hadn't been there long. There can be any number of reasons or simply no reason at all that a tom may turn and go another direction. He may have seen another hen on his way to you, that you couldn't see. Maybe he has had his butt kicked by jakes before and wasn't coming in to another male. I have had thyat happen to me many times over the years. Sometimes using a jake or tom decoy will work like a charm and sometimes it will spook them. It is really hard for any of us here to say ecactly what spooked your bird, but it sounds as if you had done everything right and the bird just went another direction.