I have missed my period (very unusual) by 12 days now onto day 13. I have taken hpt in January as had unprotected sex then around ovulation. I had a few early symptoms but had my period a little early and 2 periods since then. Now my period is missing and I have no idea why? There has been no excess stress. Or excess weight gain or loss, no new meds, no new exercise regimes. If I was pregnant I would be around 18/19 weeks is this possible?