Ay anak, I understand how scary this is, marami sa amin ang nakaramdam ng ganitong uncertainty. Please follow up with your doctor agad, or if you're worried, seek a second opinion from another OB, this is too important to leave hanging. Irregular periods talaga ang nakakaconfuse ng dating, kaya possible na off ang weeks, but only your doctor can confirm by follow-up ultrasound at checking your hormone levels. A few of my mum friends had similar scares and some turned out okay dahil talaga namali ang dating; iba naman hindi, pero either way, you need proper monitoring from your doctor to know for sure. Praying with you na okay lang ang baby mo, but please don't wait, get that follow-up appointment ASAP.