Drs appt in 2 hours.... no periods? Neg test

So we've been using the ovulation tests and have been getting surges, made sure to bd like crazy for days before and after... period has been pregressively getting later and later as the months go on? Started at 28 day cycle, now up to a 40 day cycle and as of today still no period and no positive test? ! Anyone have any ideas? Going in 2 hours to doc to see what's up $?!??!?!