Is it normal to freak out after a nightmare ?

My girlfriend had a bad dream that we got a tornado she said she was screaming and crying for me and her mom and dad but she was alone me and her parents and her horses and cat were gone and her farm was damaged she said trees were down everywhere through out her driveway she said the poles and power lines on top of her driveway were all over the place she couldn't call for help or get out of her driveway to get to her uncles house because she knows not to go near down power lines. Then she heard someone crying that sounded like a baby she said she went over to where her pool was and looked in it she said her heart broke when it was just a child's doll that sounded like a real baby. She got in and held it and sat down and started to cry. She said it was the worst dream she ever had in her whole life. She said she never wants to go through that. Luckly were in kind of a safe place where we really get tornadoes. She said she also looked out in her yard they're were bodies laying in tree branches it was like being in a scary movie. She's holding her Snoopy doll and her blankets and crying her eyes out. She said she doesn't know what to do she's freaking out like she's still in her dream. How can I calm her down ? Is it normal to freak out like this ?