I felt a funeral, in my Brain

The first line of the poem itself gives a clue to the poem being figurative. The line "I felt a funeral, in my brain" indicates that this funeral is not one of a person on earth. The reader can infer that the funeral has to do with the speaker when the speaker says, "and I dropped down, and down." This funeral of the speaker's brain most likely indicates some sort of developing madness in the speaker. The speaker is losing his or her mind. Throughout the poem, the speaker never sees anything. Most of the details come from other senses, mostly sound. This is another indicator that this is not a literal funeral because the speaker cannot hear anything if he is dead. I think I have developed a crazy theory myself: I believe that the speaker is creating this funeral because he is dead to his friends. The speaker may have lost his mind to the point where he does not appear to be the same person anymore. Because of this, his friends have chosen to ignore this mad person and preserve their memory of the speaker before he went mad.