I think I killed my two week old track hub.

yesterday my bike started making an intermitting squeek squeek squeeek noise coming somewhere from my drivetrain. Tonight I isolated the squeeking to my new rear hub.
It turns out that I managed to break the drive side locknut (i think while over-tightening the track nuts), which I think resulted in the rest of the nuts loosening and the bearings going out of adjustment.
Now when I spin the wheel, the bearings feel all gritty and squeeeeeeeeeeeeeeek.
Did I kill my hub?

and is it hard to replace sealed cartridge bearings if I did indeed kill them?
ack.