Why does iTunes delete my playlists from my iPhone when I sync to my computer ?

Hi all...

Quick question... I have the iPhone5 and everytime I hook it up via USB cord to sync to my computer (usually

To upload new CDS or just sync in general) it deletes the playlists I've made on my iPhone from the iPhone. I can still see them in iTunes but I can't figure out how to get them back on my iPhone...

Help! It's such a pain to keep remaking the lists

Thanks in advance!

Tara :)

PS: if anyone can also tell me how to sync playlists made on the iTunes to my iPhone that be appreciated as well ! I miss my automatically updated recently added/played lists I used to have on my iPhone4