Hello,
I am a teacher's assistant and worked with mentally challenged children for the past two years. We walk on many filed trips, the walking was painful at times, but it forced me to exercise, that was actually good for me.
My symptoms were annoying at work at times, and like you some days were worse some days were better.
I was able to sit down at times, and work with the students, but still I was probably on my feet more than off. I am presently taking some time off, to get on some type of treatment plan for my PN pain.
However, now that I am off, I have come to realize that since life goes on, and I am still out and about, and very active, it really doesn't matter where I am or what I am doing, the PN exists, so I might as well be working and making money.
I hope that you have more good days than bad ones!

and maybe since you teach you can have a brake during summer?
Patty