Lyric discussion by Athlete*** 

Cover art for A Bad Dream lyrics by Keane

Possibly the strongest song on the album apart from Leaving So Soon and Try Again! the meaning seems to have been covered by the above posts, the fact he's looking back at a time when he was with someone, and now that it is over, it hurts him so much, he hopes it is just a bad dream, but you get the feeling it won't be!