Here the author refers to himself as his "heart." This can be stated in active form. Alternate translation: "I am in despair" (See: [[rc://en/ta/man/translate/figs-synecdoche]] and [[rc://en/ta/man/translate/figs-activepassive]])
This is another way to describe his despair. Alternate translation: "I feel like I am drying up like withered grass" (See: [[rc://en/ta/man/translate/figs-simile]])