Is it normal to go crazy while pregnant ?

My niece is pregnant with her second child. She's been going through a lot of emotions lately. I'm not sure why. I asked if anything was bothering her or if she's worried she gets mad at me and says no. She wasn't this way when she had her daughter. She was nice and not so crazy. She's really upset right now because her and her husband were watching a show about tornadoes it's really upsetting her but she wants to watch it. She said there was a part where a woman and her husband were heading home to they're kids and house destroyed by a twister it scared her because the woman was screaming in horror for her kids she acted like a grown baby throwing a tantrum because of the storm. It scared her so much she was about ready to throw the remote at the tv. She doesn't like hearing stuff like that she cried when she yelled " MY BABIES ARE DEAD ! " she thought her kids were dead but they were alive and she cried when she came home to them then after the storms everyone even children was running around yelling and crying also scared her. She's afraid to go to sleep tonight she's worried they're might be a tornado but I checked on national weather service there's no tornado warnings anywhere u told her that but she says some states get tornadoes without warning. I don't know why she watches this if it scares her. Some days she's all happy and running around the next day she's usually crying or getting mad and yelling at someone for no reason namely her husband. It also scares her daughter when she yells that way she's only 3. Is it normal for her to go crazy this way ? How can I help her feel better ?