What is the meaning of "Amarti Chalosi Hi"?
Rashi: My thoughts say that this is only to scare me, so I will return to Him. Chalosi is like Lichlosi, an expression of Choli (illness) or Chil (fear).
Radak: "Chalosi" is a noun, like Chanos, from the root Chalal - "Ki Yimatzei Chalal ba'Adamah" (Devarim 21:1). It means 'my death' - if Galus will extend and I will not leave, and I will die there.
Malbim: The reason why Hashem's right hand seemed to change is due to my illness. The Mizmor depicts the illness of the nation as if the left hand has a fresh wound that constantly drips - "Yadi Laylah Nigrah v'Lo Safug" (verse 3). Hashem constantly stands opposite us to save us; His right hand is opposite our left. When His right hand did wonders, it empowered our hand. Really, it did not change; our hand must be healthy to receive this Gevurah!
Why does it say "Shnos Yemin Elyon"?
Rashi: The supreme right hand, which was "Nedari ba'Ko'ach