Music on iTunes

Upon opening iTunes, the bar at the bottom shows that I have 446 songs. When I click on my iPhone, and go to music, it just says Sync music (5 songs) and the same 5 songs are shown on my music library. These can sync to my iPhone, but the other 441 songs are no where to be seen in my libary or anywhere on iTunes, and therefore I can't delete them.

This iTunes is the only one that is synced to my phone and the only one that is authorised. Can anyone help me find a way to delete the songs?

martynaa98