1)
Why did Yirmeyah question his birth?
1.
Malbim: If arrows of evil of the Ma'arachah already descended on me from when I was formed in the womb, why did I leave, to be destined for numerous hardships.
2)
What "suffering and grief" did Yirmeyah see?
1.
Rashi: Churban Beis ha'Mikdash.
