iTunes Music Disappears

Hello everyone,
I had the weirdest thing happen to me. I bought an album off of iTunes yesterday. This morning I go to listen to it and its not there. I check my iTunes Music folder on my computer and it's not there. I looker at purchased music on iTunes and it's also not there. I check my iPhone and it is still there. All I did was transfer it back with senuti, so luckily I didn't lose the music. But why would music just disappear like that?

 

another question. Has this happened to anyone else?

Thanks