Just found out!

We had our 20 week ultrasound on Tuesday and found out we're having twins. A boy and a girl! We already have 3 little girls (3, 2, and 1) and we had decided we were done having kids and we're talking about who was going to get fixed and when. And then we found out I was already 2 weeks pregnant! I was on birth control at the time too. So it was a shock to say the least. But we are so excited (and a little scared/stressed) to be the parents of twins! Does anybody have any advice for us??