Hay, a delayed period with a negative PT can mean a few things, stress, hormonal imbalance, weight changes, or even just your cycle being off that month, kaya hindi guaranteed ang PT result lalo na kung early pa ang testing. Best talaga na makita mo ang OB mo para ma-check properly kung ano ang nangyari, dahil 8 weeks is quite a long delay at dapat malaman mo kung normal lang or may underlying reason, para peace of mind mo. One of my mum friends had the same situation at nag-bloodwork lang siya, kaya mas sure, kaya i-suggest ko rin sa'yo yan if gusto mo ng definitive answer!