Damn it I'm Pissed

Sorry to make a pointless thread but ugh I need to blow off some steam. So I just got an external hard drive because my laptop and my desktop had like 4 gigs left on them each. I put all my music and pics and stuff from both computers onto the hard drive. When I go to plug in the hard drive to my laptop, I open itunes and it is all of my desktops music and shit. All of this is my sisters music so it all sucks. The playlists are all messed up and everything is fucked. I have spent days at a time making my library perfect and now it is all screwed up. Luckily I still have all my music but I am going to have to perfect it again. Damn I hate computers