1st Trimester Screening - Ultrasound

Leading up to an ultrasound, I'm always filled with emotion. I'm super excited, can't wait to see this little love of mine, hear the heartbeat, etc. But then there are those thoughts in the back of my mind, you know which ones, the "what if's". 
Anyone else have their first trimester ultrasound screening yet? 
And... I'm 13 weeks this week, so happy!