Music Won't Sync?

I have iTunes 11 and an iPhone 5 that's running the latest, iOS 6.1. Last night, I put 8 new songs in my library that I wanted transferred over to my iPhone and iPad2. Every time I hook my iPhone up to my laptop via lightning cable USB and click 'Sync,' iTunes backs up my phone, prepares to sync, downloads Safari safe browsing data, and then determines tracks to sync. After it determines what tracks to sync, the sync just ends and no songs end up in my iPhone's library. I have 601 songs on iTunes, but only 593 songs on my phone. I went to the tab that shows the songs on my iPhone in iTunes and it shows the new songs, but those songs are grayed out and have a circle to the left of them. What does that mean? Someone please help :( Thanks