Taking in your new surroundings, you notice something is amiss. It's you. Whereas everyone else here is either a pig or a farmer, you are, well, yourself standing in the middle of a pig pen without a pig.
Of course, something must be done about that. Thinking back to what just happened, you come to a solution to this disparity.
"I am a pig," you say aloud. Whatever you were wearing before disappeared instantly. Immediately, you gain weight at a steady rate, your skin pinkens and becomes thicker, and you find it harder to stand up as your pelvis and legs reshape to accommodate a quadruped. Your legs shorten and thicken as your feet ball up at the ankle, harden, and split down the middle, forming hooves. Your arms follow suit, making a more dramatic change to an extra set of legs. As you make contact with the ground, you feel your tail push out and curl up into a spring. Your nose upturns and pushes out from the base, forming a snout. Your bottom lip juts out to almost meet its edge, and the skin below fattens to conceal your chin. Your head bends upward to face forward, and your neck widens until it becomes flush with your diminishing shoulder line and skull. The hair on your head (whatever is there) retracts until it becomes light fur, then spreads out all over your body. Finally, your ears pull up to the top of your head and flare out, marking the last major external change into swinedom.
Even after you finish your transformation, you can still feel minor tweaks happen throughout your body to better suit its new form. Even mental changes set in; feeling hot from the rapid change, you don't think twice about jumping into the mud to cool off. The bell the farmer rings brings you ready to eat your swill, and you eat it without a human dignity, but the manner of a pig. You can sniff out the scents of other pigs easily, and determine each pig's uniqueness. All in all, you are a pig.
Though it's not to say you are no longer yourself. That you are sure of, yet it's almost as if you were never human to begin with. You mull over your past thoughts. Coming to mind was the dream. True to the voice's word, you are unable to lie, and consequently, what you say is in fact fact. Granted, you are no longer human, and cannot technically speak, but you believe that may not be an issue.
So you stand around in your pig pen. What is there to do now?