Albert Barnes Commentary Jeremiah 45:3

"Thou didst say, Woe is me now! for Jehovah hath added sorrow to my pain; I am weary with my groaning, and I find no rest." — Jeremiah 45:3 (ASV)

Grief to my sorrow - Baruch’s sorrow is caused by the sinfulness of the Jewish nation, to which God adds grief by showing how severely it will be punished.

I fainted in - Or, am weary with (Psalms 6:6).