vaginal burning getting worse

i am a 35 year old women with 4 children. Ever since the birth of my last child in Oct. 2006, nearly 4 years ago, I have suffered from vaginal burning. It used to be only between the time I ovulated up to my period, and shortly after my period, I would find some relief. Now it has slowly gotten worse, and I have very little relief. We have lived in Africa for the last 3 years as missionarys and a Dr. here told me to use Candiderm cream which is streriod, antibiotic, antifungal cream. It seems to help while I am taking it, but within a week or two of quitting, the pain is back. I really suspect it is something hormonal, but have no idea how to treat it and Dr.s here in this country aren't seeming to be able to help me. I don't like taking the Candiderm cream for long term because I doubt in the long run that it is gonna be good, but i finally get desperate for relief! If it is hormonal how do i go about treating.... are there any home remedies I can try! I will be so thankful for any help or advice. I am married, and do have a healthy sexual relationship, but this can definately cause a bit of frustration as sometimes it gets very painful.