Talk to your ob, she will give you something you can take to stop it for the time being, just till after the wedding.  You are not the first bride to have this anxiety.  Sometimes you can be as regular as every 28 days, and then stress, and you get your period.  i think it was my sister who took something for hers before her wedding.  Best of luck to you and congratulations to the groom.  Now, relax, it is going to be the happiest day of your life so far and the beginning of a new, wonderful adventure for you both!

I have been on birth control pills for 7 years (since I had my daughter) and there have been a few times when I have skipped the sugar pills and started a new pack right away, one of the times being when I went on vacation.   I asked my obgyn about it and she said it wasn't harmful and wouldn't cause any problems.   I am doing just fine. 

Just deal with it, it's not the end of the world. If you don't already alter what comes naturally, don't start for a silly reason like that. Ingesting hormone altering drugs can lead to medical problems or cause situations far greater than the displease of having your menstrual on your wedding night!

~Zabrina