20 week scan

This is my first time blogging and I'm hoping to ease my nerves. A week from Wednesday I am going for my 20 week scan and I'm freaking out. I just want everything to be OK. This is my second baby and I think my imagination is worse this round. Every time I'm on the Internet, I always run across articles pregnant women shouldn't read and then I think the worse. Am I alone, or is this totally normal?