Why does it say "we will lie down in our shame"?
Radak: We went in our fathers' ways, and we are consumed in shame, like them. A man in great affliction who does not know what to do, he goes to sleep and lies down - "Im Tishkevun Bein Sefatayim" (Tehilim 68:14), "k'Shochev b'Lev Yam uch'Shochev b'Rosh Chibel" (Mishlei 23:34).
Malbim: We cannot lift our head and do anything.
What is the meaning of "our shame covered us"?
Radak: This is like "u'Voshes Panai Kisasni" (Tehilim 44:16).
Why does it say "mi'Ne'ureinu"?
Radak: We did evil from our youth, like we saw our fathers do.
Malbim: Since we sinned from our youth, we cannot repent.
Why does it mention both Bushah and Kelimah?
Malbim: Bushah is what one feels by himself. Kelimah is feeling ashamed due to others. The latter is the covering, for it is from the outside.