Pregnancy yeast infection

I am all about being all natural and not taking any meds while pregnant. Did it with two kiddos that way and number three has me taking something every other week. First Unisom and B6 for my constant vomiting, the. zofran in the hospital and then the next week dr told me to try Monistast for a yeast infection that won't go away and found out I'm allergic! Now she has me on nystatin cream for two weeks. Is this safe? Anyone else have experience with nystatin cream and a yeast infection?