Tell me about it- I always thought pregnancy was 9 months- then, when I was pregnant with my first, I discovered the whole 40 week thing- now, in my book, that's 10 months.
I was pretty annoyed at having that extra month slipped in on me !!!! Mind you my duaghter sorted the whole mess out by arriving 3 and a half weeks early.
It sounds like you've got it pretty right- when you have an ultrasound, they'll confirm what week you are in.

I think the due date should be on the completion of about 40 weeks of pregnancy- something like 277 days from the first day of the last period.
This is all just averages though- any where between 38 and 42 weeks is cosidered normal. Only something like 5% of babies come on the actual due date.
Don't freak out about it too much. The baby will be born eventually !!! Nobody stays in 'till they can vote or anything !!!!
Relax and enjoy. Congratulations.

Ya, you are pregnant for 40 weeks. Your due date is the first day of your 40th week.

Thanks gals. I am just trying to keep a journal and was staring at the calendar going wait a minute. Appreciate it.

good luck!

They call it 40 weeks from the first day of your last period. Actually only pregnant 38 weeks, since ovulation occurs 2 weeks after last period.

I agree with the previous posters. I've found this helpful too. Maybe it'll make it a little easier.