1)
What does this Mizmor discuss?
1.
Radak: It is about this Galus.
2.
Malbim: It is about Churban Beis ha'Mikdash.
2)
What is the question "Lamah... Zanachta la'Netzach"?
1.
Radak: Why did You permanently distance us?
2.
Malbim: There are two possible reasons why Galus extended and we were not saved. (a) He abandoned us permanently - "Lamah... Zanachta la'Netzach"? (b) He abandoned us temporarily, until His anger will subside; it did not subside yet - "Lamah... Yeshan Apecha"?
3)
Why does it say "Yeshan Apecha"?
1.
Rashi: Anyone who gets angry, his nostrils emit smoke. Radak - it is an anthropomorphism to say so about Hashem.