Radak (based on a Midrash): This refers to the nations. Those who were my confidants when I was in my land, now that I am in exile, they distanced from me.

Radak: Every person in Galus says about his colleague, due to the great affliction of Galus, one does not heed the affliction of his colleague. His own affliction suffices. Each says that his brothers, friends and confidants are far from him, as if they loathe him.

Malbim: After giving the metaphor of being buried in the grave, just he is still alive and feels pain, he depicts that his confidants distanced from him, for they despise him.

Rashi: I was esteemed in the eyes of the nations; now I am despised to them.

Rashi: I am incarcerated [Radak - in Galus], and I cannot leave.

Malbim: I am incarcerated, and I cannot come to my friends. This is a metaphor for the grave.