A new spin on re-gifting

I’ve just discovered a new spin on the “re-gifting” debate when I went shopping the other day, and I am wondering if this is a Christmas faux-pas.
I was shopping at Barnes & Noble when I found this darling gift that I knew a friend of mine would appreciate. I dug through my wallet to see if I had enough cash, and I did. But I also found something else, a $25 gift card from last Christmas. I figured that it only contained a few cents and I had just forgotten to throw it away, so I had a cashier check for me. It still had the full amount on it.
Now, I don’t remember who gave this to me, but I used it to purchase the gift. It was only $10 out of the $25, and I used the other $15 to buy things for me.
Is this just as bad as re-gifting? Should I feel guilty for using another person’s gift card to purchase a present for a third party?
The questions are neverending.

I don’t happen to think that there’s anything at all wrong with re-gifting (as long as you don’t hurt the feelings of the original giver), so I may not be much help here.

But in this case, it seems even more clear cut. Money is money. You had some that could only be usd at B&N, so you used it there for what you wanted to buy.