Firstly, don't panic. By panicking you are giving up all of your power to something that is completely out of your control, right?! The Canada Post carrier is the only one in control today.
Will there be someone at your address that can receive the card in your absence? If so, they could courier the card to you abroad. Problem solved! Make sure that if you end up having to do this, that the courier understands what is being sent, since some countries may NOT allow the importation of a card that contains a RFID `chip', which a PR Card from Canada does. Having said that, I suspect those countries are in the minority.
Good luck!