Insomnia and paranoia, what could this be, if anything?

At night, I lie awake for hours attempting to sleep, but try as I might, I almost never get more than 2-3 hours of sleep. During my attempts, my head has to be turned outwards so it's not up against a wall, couch cushions, etc, I have to wear a blanket, said blanket must cover my whole body up to my neck and be tucked under my feet, the room can't be dark or silent(if I absolutely HAVE to sleep without a light on because I'm sleeping near other people who don't want the light on, I wear headphones because I can get through my moderate nyctophobia, but I get panic attacks if I try to sleep in silence), and I feel as if someone or something is watching me even if I know darn well nothing/nobody is there, which I solve by closing my eyes and sitting up, looking around to ensure that I'm completely alone, and lying down with my eyes shut again twice, because once isn't enough to quell my paranoia.

I also can't sleep near uncovered windows and even slightly cracked doors(I'm convinced someone is watching me). I actually pinned a thick sheet over the only window in my room and barricaded my closet door(the closet door because of a whole other can of worms I'd rather not open here).

As for my nyctophobia, I've been scared of the dark my whole life. At night, when I turn off the lights in my house and retreat to my room, I run through the house like I'm the next Usain Bolt and slam my door shut because my brain screams "Run, someone's in the shadows ready to kill you" at me. (Not really, I don't hear voices or anything, it just feels like that's what it would say if it could talk. I know how insane that sounds, believe me.)

All this only occurs during the night, however, and I sleep like a champ during the day.

I really need to know what's happening to me because I'm losing sleep over this and it's affecting my everyday life. I sleep all day, stay awake all night, and can never focus in class because I'm so tired. I actually failed a test not that long ago because I fell asleep during it and quickly filled it in in about 10 minutes because class was about to end.

Any and all help is extremely appreciated