Please help me, i cant take it anymore. why are my dreams sometimes so vivid and disturbing ?

im on the verge of collapsing, ever since i was 10 ive had really disturbing dreams that include me or someone else dying. one of my dreams was where i was at the mall with my dad, and i was shot. i could tell i was dead because i felt the gunchot and i couldnt move and i was cold. i had one last night where i was in a parking lot and a man kidnapped me, and as he was carrying me into his van i saw a woman being beheaded and i would scream. then when i escaped he came back and stabbed my dad, why do i have these dreams ? im only in middle school, my family life is good. every time i wake up from the dreams i cry, and im traumatized. someone please help me, i cant take this any longer