I think that is normal. I am 18 and I still get scare of things. These couple of days I have been having trouble sleeping because I was just too scare to go to sleep. I don't know why but I was. I had to close the door and leave my light on.
Sometimes the brain acts like that when you have a fear of something or something has happen or a memory has come up.
I found out I couldn't sleep was because I was thinking to much of my past when my grandma was bleeding. ( it wasn't a lot but I have A HUGE) Phobia on blood ^^. Also that I was scare because there was a rat in the house ( I have a phobia of rats too because of the disease record here in my state)
Do you have something you are afraid of that made you scared. Like scary movie, the news, etc. ^^
I'm sure you will come down within a week. Phobias do away when there isn't anything to alarm the brain anymore. The phobia is still there it's just not as powerful.