God's name represents his character, and here, "called on your name" represents trusting God's character and calling on him for help. AT: "I called to you for help" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Possible meanings are 1) this refers to the pit that author had been thrown into. AT: "from the bottom of the pit" or 2) the author was afraid that he would die soon, so he spoke as if he were in the place of the dead. AT: "from the pit of the dead"