Apple stock goes up and down like all the others. But one thing you can count on with Apple is that it will go back up, and surpass where it was before it went down.
I suspect their stock might drop a little next week, as the expectations for new Apple products are always SO HIGH and then the actual product tends to underwhelm people at first glance. Then once it's released the servers crash from so many pre-orders and that stock shoots back up.