The song is about Mark feeling melancholy about returning home (he spent much time away from his home and family). The song is either about leaving his family behind, or ending a relationship. The chorus, "My biggest fear is if I let you go you'll come and get me in my sleep" means that if he ends this relationship, it will come back to haunt him in his dreams (no matter how much he tries to let go, he will dream about the people he left behind).
The song is about Mark feeling melancholy about returning home (he spent much time away from his home and family). The song is either about leaving his family behind, or ending a relationship. The chorus, "My biggest fear is if I let you go you'll come and get me in my sleep" means that if he ends this relationship, it will come back to haunt him in his dreams (no matter how much he tries to let go, he will dream about the people he left behind).