Candida can bump estrogen, so...

I'd take caprylic acid off and on (cheap from health food store or online; one trade-name 'capryl') to whack back Candida levels. Systemic yeast in your guts from any Antibiotic use can leave a persistent Candida colony, up to two pound worth, and this colony will, besides snitching all your magnesium, create it's own estrogen. When you cycle into your period, rising estrogen levels make the estrogen-loving Candida thrive, exacerbating PMS and can induce diarrhea. I think...