My mom has Lupus, and the ANA test (being positive) is Lupus.
A lot of symptoms are common between the two... and a lot of people with one have the other (from what I've read).
I'd go to another Doctor... there IS treatment for Lupus, there IS treatment for Fibro.... ! A doctor who says otherwise is whack!
Who treats me? *I* do.. I lost my faith in Doctors along the wild journey for a diagnoses... However, I'm sure some of the others will tell you a better option.

My GP has said I'm managing my Fibro really well (while I'm bawling my eyes out because my son is turning 6 and I can't remember any of him being a baby...)
I treat my Fibro with diet (I've learned what foods trigger it and avoid those foods)... and natural supplments... as well as exercise and positive thinking. It doesn't always work and sometimes I have to take a pain med. that I hold off for my really bad days (doctor prescribed).
Good luck and be persistent in finding an answer! Doctors don't always know everything.