Gel inserts for your shoes or orthopedic shoes (the kind they have you wear when you have diabetes...) I wore "z-coil" shoes when I am super pregnant, they are SUPER comfortable and custom fit for you, they can be spendy (maybe $50-$100)
hope it helps! the weight of your prego body is just getting too much for your poor feet! get them up off the ground a bit more and try a good soak or even a pedicure w/ a massage
The worst part is after too much time of your feet hurting it actually starts to wear on your knees, hips and lower back.... I ended up seeing a chiropractor to help alleviate some of the pain... along with the shoes i was in a belly brace (elastic and ribbed brace that pulls the weight off of your belly toward your center) and a back panel (a metal back brace that keep my shoulders pulled back)...
It was BAD! I went from being 98lbs to 215lbs when I delivered at 33weeks 2days. And keep in mind that I walked out of the hospital at 103lbs... it was all from "water" and toxemia... a good fluid flush and I was feeling LOADS better!
Congrats on getting this far! Hope you don't have TOO much longer!