I have many fears similar to what you're going through. I am very scared of people. I do not like to go anywhere alone because I am afraid that I am going to be murdered, raped, kidnapped, etc. I don't want to be a "victim" of a horrible crime and I think if I don't put myself in that situation that I can prevent it from ever happening. While I know that exercising good judgement when it comes to situations is important, I take it to an extreme level where I think everyone has a hidden motive. Even when I am at work I imagine a shooter coming in and opening fire on everyone. I also think of a co-worker snapping and stabbing me from behind with a pair of scissors.
Then when it comes to just normal interactions with people, I hate EVERYTHING I say to strangers. I can never be myself. And since I feel totally like a different person when I talk to someone I don't know well, I assume that they don't like me. What's to like? I'm awkward and quiet. It's very hard for me to get to know co-workers. I assume that girls hate me by default and they don't understand me, so I mostly talk to guys (which is often a problem with my boyfriend). I feel more comfortable with them and like they aren't judging me every second. I can be myself. I can talk about things that interest me without fear. Girls/women just freak me out. I don't trust them, either. I think they will backstab me at the drop of a hat. So I have very few actual friends...it's just me and my boyfriend.
People try to tell me that I need to stop worrying what other people think and I am being too hard on myself. People say that the things I think about myself are WAY worse than what other people think. And people tell me I need to be more outgoing and live my life. It's just really hard.