My breath is corrupt; or, my spirit is oppressed. But the physical meaning is the more probable one. A fetid breath is one of the surest signs of approaching dissolution. My days are extinct; or, cut off.
The verb used does not occur elsewhere. The graves are ready for me; or, the chambers of the grave are mine already. The plural form is best explained by regarding it as referring to the niches commonly cut in a sepulchral chamber to receive the bodies of the departed.