ANY ADVICE PLZ URGENT

Tremelda

So my periods are irregular I am pregnant but I am measuring a week behind on my last period my period always ranges between 26-30 between periods I am sure of the day I ovulated but implantation happens on the 18th when my period was due I am scared

Supposedly I am 6 weeks in these ultrasound but supposed to be 7 weeks based on last period which my periods are irregular