Talk to your parents about your feelings, you may want to consider talking to your doctor about these feelings.
it is most likely anxiety and some low deppression...but trust me if this is the only thing keeping you up at night go and talk with your mom and tell her your exact thoughts give her that one big hug and talk to her you will feel way much more relaxed!!!
I used to have that when I would sleep over a friends house when I was young..about my mom. I now have a touch of it with my spouse and children when they are off somewhere without me. I used to fear planes crashing on my house. it keeps coming back. you need to talk to your mom about it and tell her that its constant. you may be surprised how this kinda stuff seems to run in a family. it may be a form of off, or anxiety. either way tell your mom and she can help you figure out how to feel at ease. a trip to your family doc is always a good idea..always tell your doc everything, that's how they can help. hope this helps you out