The package page says I have it in the library, but I don't. I can't download my package.

@Hovl_Studio have you tired clicking on that Fab Library refresh button and closing everything out and open back again to see if you can find it there. It has happened to me once and this method worked for me. Also, restart your pc just in case and try this method. Did you download this file in proper Unreal Engine Version which can affect things too.