"i have used yaz for a couple of days now...i&#039;m not entirely sure, but i think i have pmdd. i usually have a super heavy periods that lasts 8 days. i did the sunday starter and i had my period for only 4 days. i don&#039;t know how or why, but ever since i took the pill, i feel very happy and confident. i hope yaz keeps this up in the months i plan to take it."