Whats wrong with meee??

yesterday in cl i asked the teacher if i could go to the toilet she screamed in my face saying no sit down! i then screamed and swore in her face got up, threw a desk across the room walked out the cl slamming the door behind me i dont know what that was all about??? i get moody too often i dont think its hormones!! i havent ever done something like that before also i'm obsessed with the idea of death and also me planning revenges on people....i cant stop thinking about stabbing people in the head who are nasty to me....im really morbid i have been ever since nursery school that aint a lie....i used to come home with paintings of monsters killing people every picture i did it would have blood in it...i soon got banned from takin my pictures home to show my parents as the were soo gory..i duno if its just me but its really psycho-ish ..i always think of ways of killing people do i need help????