Help, /var filesystem is defect

[Simba]

I didn't use my home pc after 4 months due of bios error, than today I can fixed it and used it again, the first thing I did is emerge sync and system. but in the middle of gcc compiling, I heard something funny with my harddisk, it make not a normal noise, its like it can't read/write something. the gcc compiling
was broken. so I just try to emerge something else like ssh, and it works fine. but some hours
later I got an error message regarding the /var file system. and when I list the /var directory,
it is nothing there although with 'df -k' I can see that it is mounted and used 60 % . I use xfs for every file systems I use here (work, home) , but I never get such problem, it seems that it is hardware defect with my harddisk where /var filesystem is, I couldn't xfs_repair it .
so the question is, if I loose my /var fs , do I have to install gentoo from the begining again?

thanks,
Simba