Why are people are so afraid of being lonely?

First, I just want to introduce myself with some details: I'm Danish and I have autism and a mental handicap. I have no friends at all and have never been on a date, never had a girlfriend. I have taken care of my mom since I was 11. I've been rejected by so many people it's just ridiculous. I've never been in any relationship ever. So what's the worst that can happen? I've been in that situation since I was 12 years old, and it doesn't matter anymore.<br>No one wants to be my friend and that's okay. I've learned to live with it, and I've learned to love myself.<br>I'm quite a loner and I'm used to being alone. I've never been a social person anyway. I just thought I would ask what's up with the fear of loneliness? I've felt lonely every day since I was 12.