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.

If you did indeed kill it, buying new cartridge bearings is cheap (I often buy phil wood bearings just on a matter of principle). You can usually have your LBS pull your bearings for you (mine does it for free), or you can buy a bearing puller, or go down to a motorcycle mechanic's shop and ask them nicely.

You can look at phil wood bearings here.

If I have one piece of advice for you, it's "go easy on your nuts." (sorry, I couldn't resist)