It cld be due to stress/underlying stress. It affects our period sometimes. I’ve had my less than 36hr period in June & was thinking it cld be implantation bleeding. Did pregnancy test at home & it was a negative. Went to see a doc coz my period has always been regular but it was nothing. I tracked my ovulation from there & tried again. I’m now 9wks along. Don’t give up!!
suggest to go gynye if this is not regular... pcos may be thr issue