Purchased album not showing up in iTunes

I purchased an album and it was in my purchased folder and synced to my ipod, but two days later I changed computers at work. The album is no longer in my new iTunes purchased folder or the iTunes folder on my C drive. This morning it was still on my ipod and when I plugged in my ipod it prompted me asking if I wanted to transfer the album to my iTunes. When I clicked OK I was told to go to the 'Store' tab and authorize my computer. I did this and now my music has disappeared from my ipod as well and is nowhere to be found. Is the music gone for good?