Heart defects?

I had my anatomy scan today at 21 weeks and found out were having our first little girl :) immediately after the ultrasound the tech went and scheduled an appointment for me to see the doctor later in the day saying that I had a lot of fluid and she (my doctor) needed to discuss the results with me. When I got to that appointment my doctor inf ormed me that they'd found a murmur and that my baby has a hole in her heart. She was very encouraging about it, saying that it was common and easily repaired but I'm still freaking out. Do any of you have any experience with this? It's never happened to anyone in my family or to any of my friends. I've researched it but that's not enough. I'm so scared.