1)
What is "Kim'at Natayu Raglai"?
1.
Rashi: My feet almost slipped [to veer away from Hashem].
2.
Radak: Every confused person leans [away from Emunah] due to seeing Resha'im's serenity. I almost said that there is no judgment and no Judge!
2)
What is the meaning of "k'Ayin Shufchu Ashurai"?
1.
Radak: I was almost removed from my Emunah to the ground. It is as if I stood without anything supporting me, for my support was so small, as if k'Ayin (it is not).
2.
Malbim: [When I began this investigation,] my steps were close to spilling from the path of happiness to denial and heresy.