Aw mama, yan ay normal talaga especially if you're breastfeeding, marami sa amin na nangyari yan, like one of my friends didn't get her period for almost 6 months kasi sobrang dami niyang ini-express, so lactational amenorrhea talaga yan. But pag concerned ka or gumagana na period mo then biglang nawala, mas better mag-check ka with your OB lang to be sure, kasi baka may iba pa na reason or baka nabuntis ulit haha.