Scan tomorrow

Hannah • Mummy to a beautiful baby girl 💕
So it's my anomaly scan tomorrow - I feel like it's Christmas <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> I'm so exited to find out if wriggler is a girl or boy and I get to see it again!!! Every day I just think is a blessing, I'm loving every moment! 
I have this little niggle...it's a worry niggle...my friend from work found out at this stage that his baby had something wrong and they were told they had to terminate the pregnancy...she then had to deliver the baby!  Even thinking about it I get teary as it was just so horrible...I keep worrying that this might happen to me! They didn't have any signs tmanything was wrong - no bleeding, baby had been moving, no pains...
How common is it at this stage for something to be wrong??