Aargh- I've just sat down after work to sit and relax to a bit of itunes relaxation and my entire library has gone, including purchases! Recent purchases the lot


I've located my itunes music folder but importing each track again will be a nightmare plus there's loads of duplicates..is there any kind of system restore that I could use?? Also file vault..that pops up pretty regularly and seems to take forever to shutdown...what exactly is it doing and why??
Heeeelllllllllppp please!!!

I've located my itunes music folder but importing each track again will be a nightmare plus there's loads of duplicates..is there any kind of system restore that I could use?? Also file vault..that pops up pretty regularly and seems to take forever to shutdown...what exactly is it doing and why??
Heeeelllllllllppp please!!!