Logan Brosemer takes a common comparison, that depression feels like drowning, and argues against it. The speaker says a better image is being lost at sea. Drowning is fast and frantic, a reflex that ends in death. Being lost at sea is slower. You know exactly what is happening, you remember when you weren't alone, and you drift wherever the waves push you.
The speaker's main feeling is exhausted uncertainty. The hardest part is the choice: wait for help that might never arrive, or paddle toward a shore that might not exist. Either could fail, and the repeated "while lost at sea" lines make the days feel long and unchanging. The ending turns the poem bleak. Hope is usually comforting, but here it is "far worse," because it keeps the suffering going. The mood is quiet, tired and heavy, and the short final line leaves it hanging.