Because of my fertile imagination and my sensibility to the world around me, I was always a very impressionable person. For me, being in my room at late night isn't always scary, but when it is, it can be very problematic. I have a bad habit of staying awake at night, using the computer when everyone else is sleeping, and when I do it, I always have a good chance of finding something online that makes me scared.
It doesn't even have to be something scary, it could be a serious information, some bizarre imagery or even a simple overanalysis. Just to give you an idea, I used to be scared of things I had read in Cracked articles, to the point of being scared of these things even on broad daylight!
And when I'm scared, I get very paranoic. I can't stop thinking that a monster could appear anywhere in my house and I start to constatly look back and around me, light up all rooms I can see, watch out for jumpscares on computer and television screens, and generally stay alert at all times. Naturally, I have trouble going to sleep in those cases, so I stay awake for even longer, sometimes only managing to sleep at 3:00 AM or so.
And worst of all, I cannot use logical thinking to avoid being scared, simply because I can't use logic to proof to myself that a monster coudn't appear out of nowhere and attack me. My only confort is knowing that if I were really attacked by a monster, I couldn't do anyting about it besides keep myself calm and wait.