My Ipod Touch 4 wont download songs

I got an iPhone about 2 months ago, and after I downloaded my iTunes library to it, the music on my iPod touch 4 undownloaded itself. I can see the evidence of the songs - the names are in gray type, but they do not play. I have tried numerous times to sync the iPod with Itunes through my computer and over wifi over the last couple of months. Last night I wiped and started from square one. I have a few songs now, but not even 50 of my 400+songs are downloaded. I have spent at least 12 hours on this and I have no clue what else to do. Help?