One thing my therapist had me do when I'm paranoid is kind of reality check. It's kind of hard when in that state (and I'm not saying you are or aren't) but maybe ask yourself why he would want to harm you? When I thought the government was after me I had to eventually realize that it's not likely that they'd go out of their way to come after me, they have much more important things going on lol. Sometimes I get paranoid about people following me too but I ask myself why would someone really follow me? I don't have any enemies and I don't exactly have money or any assets at all, if someone were trying to plot to kill me they'd have to go out of their way and risk going to prison and I don't think anyone's going to do that