Girls, good night, something's starting to panic me ? My due date acco…

Girls, good night, something's starting to panic me ? My due date according to KTR (vaginal cervix size) is today 39.2, both my gynecologist and in the maternity ward told me to count based on this term, I understand it because my cycle was irregular...but if by menstruation, then today already 40.4, even though they said to count based on the baby, I'm still worried, does anyone have such a difference in dates too? And how do you count your period? I'm completely confused (according to the second and third screening they wrote 11 May LMP, according to KTR it's May 15th, according to the menstrual