What happened so far. 

In Perek א we see that their is sadness, and loneliness. In Perek ב there is anger, and blame on G-d. In
Perek Gimmel their is blame on the people. Now in Perek Daled we see that G-d is very angry about something. In Pasuk יג It says that the priests and the prophets caused the people to sin. G-d's anger is justified.
The mother's are now cruel, because they are with holding food from their children Since their so poor.
The people used to to be wealthy and are now living in poverty. Shows how immoral and poor they become.
The Perek ends off with a glimmer of hope, and the punishment of the people has finished and the enemies who attacked will one day be punished.


The similarities of Perek ד and Perek ב

Perek ב and Perek ד are very similar.
 In Perek ב, It's all about blaming G-d. It implies that the anger is unjust and is misdirected. In Perek ד it recognizes that the people were to blame. The first section of Perek ד compared to the second half of Perek ב are similar because they both talk about her children. In pasuk ג the mother's become cruel, just like in perek ב, when the yirushalim says that G-d was angry, and let them become unhuman. The children are in the streets hungry clinging to their mothers.
The second section of Perek ד compared to the first half of perek ב are similar because G-d allowed her to be destroyed, because he was angry and caused that to happen. It also talks about the false vision of her prophets, how the other nations mock her.
In perek ד The yirushaliam was destroyed because of her sins and in Perek ב they didn't add that.
The themes that can be found in both prakim is that it's describing the hunger. It's also describing the exile and the destruction of the nation. G-d was angry so he caused this all.
In perek ב the blame is all on G-d, and in pasuk ו of Perek ד, the realization is that it's because the sins of the people that were worse then the people of סדם.