hook your ipod up and click on it in itunes, and there's like a box or something you check to take off auto-sync. I forget exactly because I've just been adding music to my phone for the past few months... haven't put shit on my ipod in a minute
you fucked man, invest in a external, and protect your files!
I have my music folder on my laptop, and every so often, move my newly required music to the external. I've lost all a huge folder before, and learned my lesson.