How do I retrieve my Apple Store gift card?

A year ago, I ordered my MacBook Pro from the Apple website and there was a deal going on where you get $110 Apple Store gift card with the purchase of a Mac. So my Mac came and so did the gift card, which was emailed to me. I bought some things with the card but still have $30 left over. Now recently, I sold my iPhone which had the gift card in Passbook and didn't realize at the time. Now I need to use it. I've tried looking for the email, but I can't find it. Is there any way I can get it back?