sweetie there are quite a few BDW brides who were mommies-to-be at their weddings so you are NOT alone. just wait, hopefully some of them will chime in.
take a deep breath! have you called him and left a message to get ahold of you when he lands?
at the most you would be what, 7 or 8 months at the wedding? worst case senario you have to make some major alterations to the dress. like you said, you were planning on starting a family in about a year, and you already plan on commiting your lives to each other, so if you are preggo, its not like you are planning a shotgun or anything people already know that is not the only reason you are getting married, so that part is taken care of! phew!
everything will be fine just breathe and get to a doc asap. did you take a digital test, or multiple tests?
and while you wait, there is a mommies to be thread running around here somewhere, you can read up on all that
{{HUGS}} and keep us updated!