Dickinson is a Mystery!

"Kept beating- beating- till I thought
My Mind was going numb-"
I felt a Funeral, in my Brain

This is going to be one of those question blogs. You know, the kind where I can't seem to figure out anything so I ask questions. The first being- why are all of these random words capitalized??!! I see nothing important about them. Let's try to form a poem of just the capitalized words.
Funeral Brain Mourners Sense Service Drum Mind Box Soul Boots of Lead Space Heavens Bell Being Ear I Silence Race Plank in Reason World Finished.
They still make no sense to me. Although I will notice that the words are composed mostly of nouns- perhaps each capitalized words stands for something else?

Well, I would next like to ask what everything stands for. Obviously, this poem involves a great metaphor. However, I am baffled as to what everything represents. Someone in our class discussion pointed out that Emily Dickinson had a fear of open spaces- maybe the poem is about her own death or entrapment alone in her house. Lastly, where is the speaker of the poem located? I believe that she is not below the floor or anything of that sort, but rather the speaker IS the floor. This is supported by the emphasis of sound and beathing rather than sights, as the floor feels steps and actions rather than sees them. Ohhhh, what a confusing poem.