You aren't 2 weeks pregnant. You aren't 1 week pregnant.

If it's 2 weeks since you conceived, then you're 4 weeks pregnant. That's the way it's measured. It doesn't matter what point in your cycle you conceived.

For example. I had a miscarriage after 9 weeks without a period. But I was only 8 weeks pregnant. Because I conceived 3 weeks after my last period. And that was 6 weeks before the miscarriage.

Weeks since conception plus 2 weeks.

That is all.