I'm pretty mechanically inclined I'd say lol im pretty sure I heard it hit the pan .Likely the oil pump shaft has dropped (hopefully) down into the oil pan. Yes you will be pulling the engine. I have heard of people that claim to have fished it out of the oil drain plug hole then used a vacuum line attached to one end of the shaft to insert it back into the pump from the top but I'm suspect of this method.
How mechanically inclined are you?