Above, it says "Tavati
Radak: Above, it discusses an affliction close to death. It is common to speak as if he already died, e.g. "ya'Yamas Libo 1 " (Shmuel I, 25:37; Naval died only 10 days later, and "va'Yamas Tachtav Mipnei ha'Ra'av" (Yirmeyah 38:9, even though he was only close to death). Now it discusses absolute death - to be permanently in Galus.
Seemingly, Misah of the heart is not physical death, rather, emotional devastation! (PF)
What is the meaning of "Tetar Alai"?
Rashi: To close on me. This is like "Itar Yad Yemino" (Shoftim 3:15) - his right hand is closed; he does not use it 1 .
For things that one does with his strong hand. (PF)
What is "Be'er Piha"?
Rashi: [This strange affliction] opened its mouth to swallow me.
Radak: If the mouth of the pit (Galus) will close on me, I have no exit from it.
What is the connection of the three hazards in the verse?
Malbim: The only counsel I have to be saved from my haters is (a) the raging current will wash me from here, (b) I should be swallowed in the depth, so they will not see me, or (c) the pit will close its mouth on me, lest I be revealed in front of them. I do not request such salvation from my haters, rather