I must admit that I am worried beyond belief, but this is due to first baby having complications which I only found out at the twenty week scan after perfectly good 12 week one, but at the time of my first pregnancy I never had much concern thinking a normal 12 week automatically meant I would have the same at 20 weeks.
This pregnancy has been worry from the beginning too as I have a higher chance of something being wrong with this baby too. And it seems like such a long wait, i have a feeling that I know myself that this baby is the same and that I will have to deliver at a larger hospital south and have multiple appointments south but at least when something is picked up you know you are getting the best care for that problem.
Try not to worry too much as that's how I am taking it day by day, most scans go completely fine and there is nothing to worry about, and like I said in the smaller chance that there is something, at least you know you will receive the care that you and the baby need
Hope I have not given a response which has scared you, that was not my intention, but I think I would have rather known about the chance of a problem arising, rather than being how I was in my first pregnancy and I must admit I hadn't a clue haha.
Am sure all will go well though, best of luck when it comes

xxx