This poem by emily dickinson is actually about the descent into madness or insanity. In the choices given above, the best way to describe it would be a mental loss. In the poem, the speaker uses metaphors relating to funerals in order to describe the current state of her mind. In a sense, we can say that in her mind, she actually lost something and is mourning the death of that "something" in her mind that she lost. In a small sense, we can say that the speaker has lost a bit of herself already, possibly her own sanity.