Why does iTunes hate me?

I had all of my music on there. Not just on there, but sorted into playlists and duplicates erased. It was great. I go to add new music and what do I find? ALL OF MY MUSIC IS GONE!!! Why do you hate me iTunes? I didn't do anything to you. Granted, I don't use you a ton but I do want you to behave yourself when I need you. Now I'm sitting here waiting for all of my stuff to re-appear (aka, adding everything back onto iTunes). And thinking about all of the work it is to put the CD's back on you and then get rid of any duplicates. Fun.

Then I can look for new music...but let's face it. By that point I'll be fed up and not do it, and then later I'll be upset that I didn't do it and get frustrated at you all over again. Yay me.