i’ve had that before, and yes it did scare the hell outta me. for my one, we were fooling around, and i started semi-spotting, and the spotting carried on for about a week. it was 10 days before i was due. and then i was late for 2 weeks. all the while testing every week. it kept coming up negative. and on the 15th day, i finally got my period. so im guessing im not at all.
one thing you should look is your family’s diet, coz i wasn’t the only one late, my mum and my sis was as well. mum was 2 weeks, my sis was 3 weeks? or a whole month i think? she’s really young, and doesn’t have a bf, so i was using her as some kind of control.
hope that helps and best of luck for you!