Drinking before you know your pregnant risks

So there’s been some talk on here about a fetus not getting nutrition from the mother until week 6. So things like drinking alcohol are no harm or risk to the fetus before that’s week.

I’ve been online trying to find some research that supports that and I’ve found none.

In fact one website says the earlier you drink in pregnancy the most risk your baby has to have fetal alcohol syndrome.

If anyone has research that says otherwise please share.

I’m thinking I may be pregnant although my period isn’t due for another week I did drink (although I have stopped now)

And I’m worried I might have done harm to the baby if I do turn out to be pregnant.