OK I'm pregnant I took a home test it was positive, I then went to the doctor the thing is they keep asking me when was my last period well my periods come and go as they want I have no clue when my last period was I guessed in the middle of march but isn't for sure they told me I was 8 weeks and 3 days is that from what I told them my period was last or do they know that for sure.

They should be able to colse the gap when you go for ran untrasound.

Due dates are guessed, educated guessed but still just a guess, based on last period, and later by the size of the baby and its development.

So don't worry about exact due date, that will be come more obvoius as you near when the baby wants to finally come anyway