Songs don't play all the way through

I have an 5th generation iPod Classic, with video, 30 GB. Since syncing it three days ago, the songs will only play the first three minutes and five seconds. Then it moves on to the next song or if it's the last song, it goes back to the menu. I just synced again and it it still doing it.It also has a small group of dots near the middle of the screen that weren't there before.Has anyone else had this problem or know how to fix it? Thanks.