Hi there! I understand what a scary situation this can be! I was in your shoes with my daughter, my second born child, I had a lot of troubles with my pregnancies with miscarriages then I really got lucky and my son was born weighing 10pounds 2ounces after giving up on getting pregnant and then we had the scare with our daughter with the drs saying she would be born with downs syndrome and I cried and cried and at that time, I was working at a state hospital with mentally challenged or special at that time they called them retarded children and then, I decided that I was going to think and be positive, my daughter did not have downs syndrome she is a young adult now. Sshe has two years of college down, almost three and even if she did have ddowns syndrome, I would not have loved her any less, I would have taken care of her. You have some good odds and try to be positive thinking that the baby to be does not have downs and if he/she does you will deal with it when the time comes.
The best to you and yours!
Please keep us posted on what you find out and feel free to vent or talk anytime! We are herer for you!