this happened to me as well. you can only get Shingles if you have already had chicken pox and it can only be transferred via direct skin to skin contact. you would have had this contact with that person? try not to worry, my doc told me that i would have had to literally touch the blisters of the person that had it (eww!) before i would get it...
hope that helps. maybe give your doc a call if your worried.
congrats on the pregnancy btw - you will be able to tell people soon!
Mrsmorgie2b is right. So don't worry