@Clomid1, it is quite scary, and bad things do happen occasionally. But as you said, the vast majority of people have uneventful pregnancies and see they babies grow up.
Try to keep in mind what you can control, and that is only your own actions. Anything else is out of your hands, and we will just have to trust God, the universe, fate, or whatever you believe in. For now, you have made it this far in your pregnancy. Try to take it one day at the time.
If you find yourself struggling to turn these concerns off and they start stressing you out on a regular basis, it might be worth bringing it up with your midwife.