1)
What is the meaning of "Shachah le'Afar Nafsheinu"?
1.
Radak: We are close to death; the Nefesh is close to leaving the body. When will You save us?!
2.
Malbim: This is Galus of the Nefesh.
2)
Why does it say "Davkah la'Aretz Bitnenu"?
1.
Radak: One who falls, he leans on his hands. If his hand slips, his stomach clings to the ground.
2.
Malbim: This is Galus of the body.