When I got home, I looked at the receipt when I was taking my things out of the bag, and noticed some things:
-it confirmed that my total was $25.80, so that's fine
-it said that I in fact DID have $29.90 on my giftcard. none of this total was paid with said giftcard.
So basically, not only should I have a giftcard with $4.10 remaining, but I have an extra $25 gone from my checking account that didn't have much to begin with, and some evil employee went on a mini shopping spree. Or maybe I'm just really cynical and she was just stupid, haha. I'll check it out when I have a chance to go back and get this resolved, ugh.