Within a Dream Reflection

I think that in the poem Edgar Allan Poe tries to get across the point of how do people know yet aren't in a dream. In the poem he says "In a night, or in a day,
In a vision, or in none" and this leaves the reader with a mystery that he leaves for us to figure out. Also, when Poe says "Grains of the golden sand-
How few! yet how they creep
Through my fingers to the deep" i think he used golden sand to represent how there are important things in life but he says "how few" to show it is rare but if you don't try to embrace it it could slip away while you sit and watch.