Ay, ang confusing talaga ng ganyan, mama! So based sa timeline mo, Dec 25 ka nag-start ng pills, tapos nag-bleed ka lang ng Jan 20, so technically around 27 days delayed? That could be normal, honestly, especially if the pills disrupted your cycle (pills can do that, lalo na if nag-switch ka suddenly), pero yung "ganyan na lumabas", paano ka nag-describe, heavier or different texture than usual? A few of us mums had light bleeding or spotting early on tapos akala namin period na, kaya di kami sure kung pregnant or not. The tricky part is PMS and early pregnancy symptoms look almost identical, breast tenderness, cramps, backaches, even nausea, lahat pwede both, kaya ang safest move talaga is take a pregnancy test, ideally bukas or within the next few days pang, para accurate. If you want peace of mind, I'd swing by a clinic or pharmacy para magtest, or kahit ask your OB directly kasi alam nila ang medical history mo. Better to know now than stress pa more, diba? Rooting for you, and whatever it is, your doctor can guide you best.