What does my dream mean?

I had a nightmare last night. I was at school on the last day. We were supposed to be doing a test. I totally missed the test, because I was looking outside. The clouds were pitch black. Then I heard a tornado siren, and we all quickly ran down to the shelter with my teachers. A plane landed in front of us with bodies inside. I managed to crawl out, and the whole place looked terrible. I couldn't find my mom or my little brother. The teachers wouldn't let me leave. So, we went in the parking lot. All of a sudden, another tornado comes. We run back. Almost everyone dies at that point. Two men, a women, one of my teachers, and a close friend are there. One of the men takes a sip of water in a cracked glass. It turns out the other man put glass in there to kill him. I cling on to my teacher, and I see the woman cackling. She takes us to a 'palace' as she calls it. It's basically like a factory or a prison. There are children walking all around, but they're all brainwashed. There's also a room full of psychopaths. My friend sees a door with a parking space behind it, and runs to open it. An alarm goes off. A little girl, about 12 or 13, tells the 'Queen' that he accidentally leaned back on it. She goes into a room with a concert playing. The girl tells us it's a room for people with Tourettes behind it. There's also an exit there. She tells us no one has ever escaped. She agrees to help my friend escape, and he does. He goes to tell everyone about what happened. I go with the girl, and I find my teacher staring into space. I tell him to come with us. It's dinner time. Her job is to open all the doors to let the patients out. There are frightening bald Frankenstein looking guys. I woke up in terror, heart pounding. Someone tell me what the heck this means?! Thanks