Just in response to the posts on the dangers of scans - They have never tested many things to prove if they are safe or not, including most things pregnant women are exposed to - because those sorts of experiments are not ethical, so they will never be done.
However, there are no recorded cases of any number of scans causing issues which is why they are considered safe and not limited during pregnancy.
One extra scan, in the scheme of things is not really anything to be worried about - you would have more to worry about with pesticides and other chemicals we are exposed to on a daily basis.
But, OP you do what you are comfortable with, I understand that the fear of finding something wrong can be overwhelming.
Good luck with it all.