Mama, I really think you need to see your doctor ASAP about this, kahit routine lang dapat na-check ng OB mo, lalo na't birth control-related ito.
One month without period while on pills can happen, pero better safe than sorry, ha? A few of my mum friends had similar concerns and their doctors reassured them agad after a quick check-up. Kaya please don't delay, go to your clinic or call your OB para malaman what's really going on. Take care, ha!