Up Next iPhone gets crazy

Hi Guys,

My problem can be simple to understand and probably easy to fix, but here it is my doubt: Last week, when I was listening music, I've done something in my iphone that all songs, since then, are being repeting. When there is a song playing, cliking in "Up Next", there is a huge list of song, but the same song. What I should do to organize that? Just to remember, I have a almost 800 song there, so it's impossible use the "clear" one by one :D

Thanks, guys.