i keep hearing things, i need help

i met this guy named lucas in a server. and i dont know why, but something drew me to him. we both have very similar interests. hes a total piece of shit, but i cant help myself. im so oblivious to everything wrong that he has done. all i ever do is admire him and daydream about me and him, and nobody else. i just want to take him from everyone else, so i can just have him to myself. but just as soon as i thought i finally got him out of my head, i start hearing his voice in my head. over, and over, and over again. he keeps telling me to do horrible things. but it cant be him, right?? it feels so real. i feel so weak and so tired all of the time. hes ruining my life. someone please help me get over him. im in so much pain. he doesn't know how much pain he's causing me. please someone let him know. i hate him.