I had thrush for 4 months after DS was born. I went to diflucan pretty early, after gentian violet and GSE didn't do much. On the diflucan, my symptoms went away. But each time I went off it, the thrush came back
I ended up doing 4 rounds of diflucan. During the 4th round, I finally "gave in" and started the anti-candida diet (no grains, dairy, sugars (except stevia), and limited fruit - basically lots of meat, eggs and vegetables). I also switched from the APNO to an herbal ointment I got from my naturopath. I also continued with GSE washes, etc. Put all together, I finally beat the thrush and it never came back.
So, if you've tried everything else without success, I think the diflucan is a great next step. I urge you to try some of the other changes, too.
More Info: Although you say you've done "all the other steps", I don't know exactly what you've tried. So:
* look into Jay Gordon's grapefruit seed extract protocol, if you haven't already.
* If you are using APNO, be sure to use it sparingly and only three or four times a day. I used it after every feeding and ended up with an ulceration on my nipple that forced me to pump that side for 5 weeks while it healed.
* Use a fresh towel after every shower, and use a new handtowel or switch to paper to dry your hands while you are still fighting thrush.
* Wash all towels, bras and underwear (and shirts/sheets, if you go braless or leak onto them) in HOT water and dry on HOT. You can also add vinegar to your wash. It is common to reinfect yourself. I used disposable breast pads and changed them twice a day. I also bought a cheap pack of washcloths at Target to use for hand and breast drying, using each only once between washes.
* Somewhere on this forum is a "Fighting Thrush Tribe" thread with lots of great information in it.