Meaning of にがな in Japanese

この仕事は何が何だかさっぱり分からないわ。
I can't make heads or tails of this assignment.

あなたが死ぬまでに何が何でも達成したいことはなんですか？
What is it that you want to achieve, whatever it takes, before you die?

何がなんだか分からない。頭がパニックに陥って整理がつかない。
I didn't know what was what. The inside of my head had gone to panic mode and I couldn't get things straight.