Q: I have an iPod nano and I had purchased from iTunes random songs and downloaded lots of my personal albums and now they are gone from my iTunes account and they are in SyncUp.  I never meant for that to happen.  How do I get them back to my iTunes account

I have an iPod nano.  Somehow an update for SyncUp appeared and I updated it.  Now all the music from my iTunes account including songs I purchased and my own personal albums are all on SyncUp.  I definitely did not want that to happen.  How do I get my music back to my iTunes account?  Thank you.