I recently developed an irrational fear of being stalked, tortured, and killed. it makes me afraid to be alone at home. how can i get help?

Beliefs matter: I would recommend making an appointment with a psychiatrist to discuss your irrational fear in detail and to get some help in relieving it. The psychiatrist would do a complete mental health exam and determine what is the basis for this fear and any other issues that might go with it. Then, a treatment plan would be organized to provide symptom relief and to address any underlying issues.

Psychiatry: Today, it's not lying on the couch and talking about your dreams. What you describe is quite common and even though i'm not a psychiatrist, it can usually be effectively eliminated with a short course of cognitive-behavioral therapy and perhaps a small dose of a single medication. It will be good pain, like lancing a boil. Be brave and do what you must, or it will get worse and worse.