Lost my whole library in transfer from iPod to MacBook.

There's actually no built-in way to transfer music from an iPod to your computer. This is an intentional feature meant to prevent piracy and preserve Apple's DRM scheme. There are a few programs that worked with older iPods which would allow you to transfer music from an iPod to a computer, but your milage may vary depending on your OS and iPod model (but it sounds like at this point your iPod is already wiped).

You may have success enabling disk usage on the iPod, then running a data recovery program to get your files back, but once again your mileage may vary depending on how much you've used it since then and how thoroughly iTunes wipes an iPod on a fresh sync. Let me know how/if it works!