After buying a new iPod Touch songs from my computer's library keep disappearing and I can only access them on my iPod. How can I get them back?

I recently purchased an iPod Touch (5th Gen). After connecting it to my MacBook Pro a few times, songs have disappeared from my laptop's library. About a week ago all of my songs were removed and I had to re-download them (with the cloud/arrow button). But only about a 10th of my songs are available on my laptop. When I connect my iPod, if I select the iPod, all the songs reappear on my list, but I can't edit anything from my laptop (make new playlists, move songs around, delete, add, etc.)

What happened? How do I reverse this? I thought maybe it had to do with the cloud. But I've never officially started using the cloud. My iPod says the cloud is off. It does say that I won't be able to use songs in the cloud on other devices unless they're all up to date. So, I checked and I have no updates. It's strange because there doesn't seem to be any pattern to the songs missing. Some are purchases, some are CD downloads. Some of the purchases are new, some are old.

Any suggestions?