Why does it mention "Hashem"?
Radak: He is Master of everything; I sought Him on the day of my affliction.
What is "Yadi"?
Rashi: My Makeh (wound). Radak - this is like "Hinei Yad Hashem Hoyah" (Shemos 9:3). The Makeh is the moaning and pain of the heart due to Galus.
Why does it say "Laylah Nigrah"?
Rashi: In this Galus, which is like night, fluid and Marah (bile) flowed [from my wound].
Radak: At night, man is free from worldly pursuits, and thinks about his matters. Nigrah (flowing) is a metaphor for the constant sighs, one after the other. This is like "va'Yitechu cha'Mayim Sha'agosai" (Iyov 3:24).
Malbim: Even though I sought Hashem on the day that my affliction came and I requested respite and salvation, he depicts that his hand flows due to the wound. This is a metaphor for thinking that Hashem's hand, which supports him, became ill and weak (verse 11).
Why does it say "v'Lo Safug"?
Rashi: Does not cease [fluid to flow from my wound].
Radak: My Makeh will not soften or weaken. It always flows. This is like "va'Yafag Libo" (Bereishis 45:26).
Why is his Nefesh not consoled?
Radak: Even though I put consolation to my heart, that Kel will take us out of Galus, even though it lengthened, my Nefesh is not consoled, due to the many afflictions.
Malbim: It seems that also the hand above, which was his help, became weak and has no strength.