In what way does the line “sags like a heavy load” in "harlem" relate to the overall feeling of "the weary blues"?

The poem entitled, "The Weary Blues" is a poem written by the then very young poet by the name of Langston Hughes. The concept basically of the poem is being burden and sad. Similar to the line "sags like a heavy load" where in the speaker or the writer was also burdened. 

my way or the highway

Explanation:

so daddy said uwu sucky wucky my we we o~

but ya is B no need to thank me im just that GrEaT