I don't really have a device with a playlist right now, but I do listen to Spotify sometimes, so I went into my hodge podge playlist and clicked until the 10th song came up. I had to chuckle because this is the song I would use for theme song prompt too. :)
Anyway, the song is Titanium by David Guetta, featuring Sia. I have most of Sia's work, including her albums with Zero 7, so I really enjoy her singing. This song really is that coat of armor I use to get through those tough times during the school year.