I have noticed light activities seem to help my feet. For instance working in the yard: stacking wood, cutting grass, tending to the garden, etc. Oddly bike riding seems to cause problems for me. If activity works for you, I would keep it up, since it has many other benefits.
There are a number of things you should consider trying or ask about: acupuncture, massages, PT, lidocaine patch 5% (I am trying that now), electronic muscle stimulator (try it and then buy one for yourself. My wife has one and it doesn't seem to help me.). For severe pain you can try a TENS unit.
Also, you can step your Gabapentin up to 3000mg. For folks who max out their Gabapentin to that level they pair it with an anti-depressant to enhance its effects. But I see no reason why you cannot ask for that before stepping up your dose.
There is also a time released once per day form of Gapantin now called Gralise. It might work better for you.