I second the no soap thing, though can take it a bit further - I had this problem for years & thankfully don't any more - I really feel for you its no fun at all :(
Have you tried cutting out chemical additives from both your diet & soaps/bubble baths etc - shampoo too if you use in bath or shower & it can run down below
- colourants & Benzoate Preservatives are the big culprits, but artificial sweeteners cause me problems too
Ironically I discovered this when DD was tiny - she started up with the same sort of problems - poor might was an absolute mess down below & GPs didn't seem to have a clue - nappy rash, thrush etc, but nothing they gave helped at all - she had running sores :( -
I hadn't considered diet at all, because it was pre weaning & she was EBF
but I'm lucky to have an old friend who works in Alt healthcare & specialises in DCs - she suggested it was what I was eating passing through breast milk - I used to get pre-menstrual cravings for cheap jelly kiddy sweets & still got these craving during BFing -
I stopped eating anything containing them for DDs sake & then realised it helped me too - & later realised the same with shower gels, soaps etc etc - DD is badly intolerant to any of this stuff & it shows up as Exzema - with me it shows up as the thrush like symptoms you describe.
I used to blame thrush coming on the run up to my periods - turns out it was my craving & the chemicals I ate then, but not at other times that was the real culprit - I only ever have odd flare ups now if I eat or drink foods, or use bath stuffs with these additives - so I avoid:)