Rashi: Yirmeyah laments about himself. The people of his city hated him for his words of rebuke.

Malbim: According to the parable, I brought a young plunderer against the widow; this refers to every mother. The parable hints to a great city in Yisrael. He discusses his mother, i.e. the city that is his mother. He laments that she gave birth to him to prophesize about this. The Midrash gives a parable of a Kohen who gave a Sotah to drink the cursing water, and then saw that it is his mother. Hashem told him that the remnant will be given to the sword; he and his mother are among them. He laments that he was born to see misery and agony.

Malbim: Until now, there was hope that he would return them in Teshuvah. However, now that his Tefilah was not accepted, and the decree was sealed, his only involvement with the nation is to quarrel with them, and not to help them.

Rashi: It is a quarrelsome person. This is like "Lo Yadun Ruchi" (Bereishis 6:3). Radak - this is like "Ish Riv"; "Madon" is like Riv.

Malbim: Riv is when there is no claim - correspond to this, he said "Lo Nashisi". Madon is when there are claims. Corresponding to Madon (when there are claims), he said "Lo Nashu Vi". Madon is when there are claims.

Rashi: This is like "Lo Sihyeh Lo k'Nosheh" (Shemos 22:24). (I am not a pressing creditor.) Radak - they hate me only because I rebuke them, for their benefit!

Rashi: I do not quarrel with them about monetary claims that I have with them, nor they against me, yet the entire nation curses me!

Radak: Mekalelavni is a compound of two roots - Kalal and Kalah. Kelalah is the opposite of Brachah, and Kalon is the opposite of honor. Yirmeyah says that everyone curses and disgraces him. He said both in one word for brevity and clarity. The Hei in Kalah was switched to a Vov, like is often done. Had it not been switched, the pronunciation would not indicate Kalah.