half of garageband files deleted

Hey I have a question. I make music for a channel, and today I came on my iPad to do some music on the GarageBand app. I noticed that half of my music disappeared on grarageband and I can’t get them back. Is there a way I can get them back some how? I’m very confused as to what I can do because the most valuable ones are gone.

May it have been the update I did?