Late period??!!

Leah
Hi looking for advice, today is 39 days since my last period,i have pcos but always have periods from 21-24ish days,iv taken tests all negative,i dont have sore boobs but i just dont feel myself,sluggish emotional. On cd 21 i got very light pink spotting lasting 2 days i thought AF was coming but never did! Surely if that was LB it would show on preg test by now? Iv had light dull aches down there for 2 weeks but no sign of period and cant get a docs appoitment. How common is it to not show up on preg test on day 39?? Any advice would be greatly appreciated x