Am i having night terrors? ?

Ok I am 17 years old, and ever since I can remember my dreams have always been nightmares, but worse. I feel as if I am really there or sometimes Im just watching but can't do anything about it. It always has to do with someone I know or myself dieing. for example, last night I had stayed the night at my boyfriends house and I was the only one sleeping upstairs and In the dream I was just laying in bed looking around the room like I couldn't sleep, then the door starts shaking violently n I jump up against the wall then the walls start shaking n I grab my ears to block out the sound then it stops n the door swings open n there's a face, it flies towards me n goes straight through me n out he wall behind me. I run down the stairs but fall n cut my knee. at the bottom of the stairs there's a window I see a scary looming man n I run to the couch where my boyfriend is n Im trying to wake him up but he don't move I turn around a scream trying to get someone to wake up that's when I woke up to me screaming, crying, heartracing, chest hurting n out of breath, frantically checking my knee. n running downstairs to check on my boyfriend. I remember them as if it had really happened every horrible detail. I've been sitting in a truck n get shot in the chest n watch myself die. I've had to call friend at 3 in the morning panicing thinking they were hurt. it only happened every few months, Im fine after I realize it didn't really happen. but I really wanna know why I do this or what causes it. can anyone help me??