I think the song means when she says ive got nowhere no one without you boy im done, i think she is feeling guilty that her husband has passed away and wants to join him in heaven but because she said devils dont fly, she is in hell because she commited (aka suicide). she also says ive been thrown out cast out when i crossed to the other side, meaning that when she killed herself she went to hell and heaven will not accept her for killing herself.
thank you for listening