IPod Nano Music Not Showing Up

Hi. I have an old 5th Generation iPod Nano with 16GB of storage.

I also have a Mac Mini running OS 10.13.4.

I haven't used the Nano in years, though a year or so ago I tested it and added some music to it and it worked fine.

However, I tried using it again tonight and I'm having some issues:

The iPod shows up in iTunes when I connect to my Mac. In the "On My Device" section of iTunes, when I click on "Music" and "Podcasts," iTunes shows music and podcasts on the iPod. However,when I disconnect the iPod from my Mac, the iPod shows 0 songs and 0 podcasts.

I even removed all the music from my iPod by unsyncing it, then re-synced it. And I'm having the same issue.

Also, I just noticed: on the iPod, when I go to Settings, the iPod says Free Space is only 394MB and that there is 14.6GB of data used under Other. It shows 0K for Audio.

Just wondering if anyone knows a fix, or whether my iPod sounds broken.

Thanks!