Symbolism in "The Things They Carried" - the emotional burden acting as a physical one

I am only half way through an essay about discussing symbolism in this short story. Besides citing the emotional burden acting as a physical one, I appear to be stuck and can only say the same thing so many times...

I remember reading this in college. Or, more accurately, I remember my English professor discussing this. Not sure if I actually read it. Whoops.

I do remember my professor talking about "humping" as word for carrying. So think about the implications of that. What is the difference in humping vs simply carrying? Also, think about the things they carried that weren't physical and how "heavy" each of those non tangible things weighed. What do the physical things they carry mean? How do they relate to the emotions they carry? The physical items are a manifestation of the emotions, but the emotions are much deeper and stronger. Think about certain characters, objects, or scenes and what they could symbolize. What about their mental state and the effect war has had on them? What are some common elements that keep cropping up?

If all else fails, a quick internet search should give you some specific symbols that are important. I know I found some rather easily.