Did he truly say so?
Rashi: He thought so in his heart, amidst his great afflictions.
What is "Nitzchi"?
Rav Sadya Gaon: My salvation.
Rashi: My world and my hope.
Ibn Ezra: It is my blood, which stands one up for his Netzach (allotted years) - "v'Yetzer Nitzcham Al Begadai v'Chol Malbushai Eg'alti" (Yeshayah 63:3).
Palgei Mayim: My hope to exist forever. Amidst my afflictions, I said that it was lost.
What Tocheles was lost?
Ibn Ezra: I have no hope to see good again.
Ri Kara: All hope should have been lost. I was incarcerated in a dark place. There was a stone wall around me. My legs were shackled in heavy fetters. The jail was totally enclosed, so my screams could not be heard outside. Even if I could break the jail wall, I cannot return on my path, for my path was made crooked. A bear waits in ambush. It is futile to scream, for my Tefilah was sealed. Refer to 9:19:3:1.