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!!