Urinate before and after sexual experiences and eating yogurt helps.
It is good you are wearing cotton panties and changed soap etc....eating yogurt is helpful with yeast infections. Are you taking any antibiotics, perhaps for acne? They can cause yeast infections. Also oral sex can cause yeast infections if your partners mouth has a high population of yeast. The pH of your vagina may be off as well. Vagisil has an over the counter screening kit to test pH. If you have only tried over the counter stuff for your infections you need to go see a doctor to get it straightened out! Good luck!