This song is from Scottish band Biffy Clyro’s 2007 album Puzzle. The album largely deals with the death of the lead singer’s mother.

About the song (from an interview quoted on Wikipedia)

It’s about not wanting to waste your life, but about having no idea where to turn and suddenly being aware of your own mortality.

He also added that it is “about hitting a low point and not giving a fuck. It was classic depression, I suppose.”