Added music not showing neither in the library, nor in the recently added I've got a 1040 MP3s to add to iTunes (not bought before).

I dragged them to the iTunes window, it processed/copied something (only 953, huh, why?), they even appeared in the iTunes Media/Music folder and in the iTunes Music Library.xml file. But I can't find no one of them neither in the library, nor in the recently added. Interesting thing: there is a new album cover on the cell with the name of the artist existed before. And if I search a random song in the search bar I'll find it but I can't go to it or add to the next playing.

I haven't the iTunes Match option.

What is happening?
It took a time for iTunes to process a huge bunch of files so now they appeared in the library. However, there is no progress bar or something like this to recognize when it'll finish.