Laura - First of all, congrats on your pregnancy!! That's wonderful! I just want to say, and keep in mind that I have no firsthand experience with this, so I'm sure it's easier said than done, but it seems like the best thing to do is relax and enjoy your BFP for now. I'm of the mind to not invite trouble and stress into my life. Sure it crashes my party upon occassion, but I'm happier if I don't seek out the worst case scenario. I think it's good to be knowledgeable about things but take it easy and enjoy this time. I know that's hard when you're used to getting bad news...but now it's finally your turn to celebrate though so enjoy it!
I wish you the best!