music not on icloud is gone from library and Itunes wont add what's on my computer or save it

i have tried to re-add and it wont. the only thing that shows in the library is ICloud only. i had WAY more than that in it yesterday! i was able to re-add all of my music once and its gone again for some reason it's not saving it what's going on? i have uninstalled and reinstalled and that didnt help any.