Yeast infection advice

Just want to vent for a second. Or maybe if anyone has any advice. I get chronic yeast infections that have been ruining my life! I get them habitually a week before my period. Sometimes randomly, also. I was worried that maybe I had contracted something without knowing but I went to the OBGYN and got fully tested for everything- all negative. I have changed my lifestyle in attempt to fix this and so far I haven’t had any luck. I do not use any scented lotions, soaps, douches, wipes, detergents- anything. I don’t drink alcohol. I stay very clean down there. I only wear cotton underwear. I don’t wear underwear at night so she can breathe. I eat a very healthy diet. I’ve taken probiotics, have used tea tree oil, apple cider vinegar: It has just become too much. I am in a serious relationship and this is damaging my sex life and self esteem. I feel helpless! My OB was wont prescribe my anything to quickly get rid of them- so I resort to Monistat which is expensive and adds up when you have to buy it as frequently as I do. Does anyone have any advice?