Missing songs after 8.0 update and sync I did the iOS update a few months back and noticed that the songs I had downloaded in May and June 2014 were missing. Since the computer I used that had iTunes was stolen in July 2014, I had no way to access iTunes. Finally tonight I was able to plug in my phone to iTunes on the computer. The playlists showed up with the missing songs in them. I then selected sync hoping they would be moved to my iPhone 5, Instead my playlists are now empty. Is there a way to get my songs back?
Everything must first be on iTunes before it can be put on the iPhone. If the playlists and songs are not on iTunes on this new computer, it won't work, and syncing will only erase what you have on the iPhone, as it apparently has. 

In this case, all you can do to recover is:


Restore from a backup previous to trying to sync music to this new computer, recovering the previous, imperfect iPhone state, or 
Ideally, get the playlists and songs all loaded and working in iTunes first, then you can sync them to the iPhone.