Did she tell you why she sold it? Is she wanting to sell more? If I wanted to keep the friendship I would sit her down and see what is going on. I would tell her how much it cost to make and if she was planning on selling another then we needed to make a deal. Tell her how you felt about her selling a gift. If I made her another I would make sure her name was on it in several places. I think they are very cute and a great craft show sellable item. Sit her down and talk if you want the friendship otherwise this will fester and ruin the friendship.