Hello,
We should remember that the Book of Lamentation is a lamentation over Isreal during the two ages that they would walk contrary to God during the third and the fourth age of the existence of Israel from the time of Isaac's birth.
The Book of Lamentations was not written as a lamentation over Israel because of their 70-year exile into Babylon.
This is how I understand the end of the Book of Lamentations: -
Lamentations 5:7-22: -
7 Our fathers sinned and are no more,
But we bear their iniquities.
8 Servants rule over us;
There is none to deliver us from their hand.
9 We get our bread at the risk of our lives,
Because of the sword in the wilderness.
10 Our skin is hot as an oven,
Because of the fever of famine.
11 They ravished the women in Zion,
The maidens in the cities of Judah.
12 Princes were hung up by their hands,
And elders were not respected.
13 Young men ground at the millstones;
Boys staggered under loads of wood.
14 The elders have ceased gathering at the gate,
And the young men from their music.
15 The joy of our heart has ceased;
Our dance has turned into mourning.
16 The crown has fallen from our head.
Woe to us, for we have sinned!
17 Because of this our heart is faint;
Because of these things our eyes grow dim;
18 Because of Mount Zion which is desolate,
With foxes walking about on it.
19 You, O Lord, remain even to the vanishing point in time;
Your throne will still remain for an age plus an age. {i.e. after two ages}
20 Why do You forget us for so long a time beyond our ability to grasp,
And forsake us for such a long a time?
21 Turn us back to You, O Lord, and we will be restored;
Renew our days as of old,
22 But You seem to have utterly rejected us,
And are still angry with us!
The above passage is the NKJV with my mods in verses 19-22 to improve clarity.