It seems to me that he had 2 friends that were living with him, and the 2 where going out, one being 'jenny' and as it happened, this guy broke it up and went with another girl. As being friends with her too, he may be taking her side, singing his anger to him, saying 'everyday a bad day for you' - for what he did to her.
The song is out of revenge for sake of jenny, but the last lyrics ' but i'm sorry if it ever is' shows that he is still friends with this guy.
I think he is singing on behalf of a friend.
It seems to me that he had 2 friends that were living with him, and the 2 where going out, one being 'jenny' and as it happened, this guy broke it up and went with another girl. As being friends with her too, he may be taking her side, singing his anger to him, saying 'everyday a bad day for you' - for what he did to her. The song is out of revenge for sake of jenny, but the last lyrics ' but i'm sorry if it ever is' shows that he is still friends with this guy.