Claire, I have had this a few times and it always scared me because I've had kidney stones before, and I also had an early kidney infection once.  But I always got through it and haven't experienced any kidney pain in quite a while.  One thing that helped a lot during those times was applying warm moist heat in different forms: warm bath, drinking warm/hot water, hot water bottle on abdomen/bladder area, or applying a warm/hot washcloth to the abdomen/bladder area.  All that warm moist heat helps the bladder to relax and empty more completely and somehow that always helped my kidneys to feel better.  Not sure exactly how it all works, but when I've gotten into a real pickle with my bladder/kidneys, Dr. M always told me "warm, moist heat." 
 
I don't know if this is related to anemia.  I had iron-deficiency anemia several years ago, but not during treatment.  I do notice though that I crave red meat even more during my period and it definitely gives me more energy during that time.
 
I just want to reassure you that it's going to be okay.  You are in good hands with the Brizman's and even though this healing process may take longer than we would like, it is happening.  
 
Blessings,
 
Lisa