This one resonates so much with me right now so, here you go, I think its pretty dark and it's cool too
And if you really want dark songs with dark lyrics, you should give a try listening to teen suicide, flatsound and dandelion hands.
^ this one from flatsound gets me
everytime
I want to give a special mention to the antlers and his album hospice, one of the saddest and more devastating albums i've heard in my life, it tells the story of an abusive relationship within a patient with terminal cancer and his partner who works at the hospital and has to take care of her.