1)
Why did he say "Nishkachti k'Mes mi'Lev"?
1.
Radak: [My close ones] fear so much for me, to the point that they despaired and I was forgotten from their hearts, like a Mes is forgotten from the heart of his lovers. They have no hope that I will return to them.
2.
Malbim: Even though I am alive, I was in their eyes like a Kli destined to be finished off.
2)
What is "ki'Chli Oved"?
1.
Rashi: It is about to be lost. 'Aveidah' does not refer to the one who lost it, rather, the item is lost from him - "Asher Tovad Mimenu" (Devarim 22:3), "ha'Ovedes Lo Bikashtem" (Yechezkel 34:4).
2.
Radak: They despaired from me like one despairs from a lost Kli.
3.
Malbim: Refer to 31:13:1:2.
