I can somewhat relate because I've had no experience with the opposite sex. It's not that I'm unattractive, I've been told that I am 'really cute' by other people but really, I don't see what they see. I think of myself as the girl who has a crooked home hair cut fringe.
It sounds like your anxiety has impacted your relationships. You don't need to always be 'fun' or 'exciting', some people just accept you for who you are. I suggest at least being open to hanging out with a friend once a week or even once every two weeks.
Have you thought about seeing a doctor or a psychologist? I am recently on antidepressants, and it has made me feel more 'stable'. My psychologist listens to me and helps me too.
I get your sense of failure with jobs. It's like you need to trust yourself. You can do it.
I'm also like you, at first when you meet me, you think that I'm weird, awkward and nervous. But I have been called a comedian and outgoing too.
I'm 21, I wish I had a job because I am financially independent from my family. I've been to 3 interviews so far. I think when I get a job, I got to trust in my ability and rationalise with myself that what my brain is telling me is not true.
I'm 21 and I have never really been on a date, or had a kiss or had sex with anyone. I know that some of my friends have gotten in relationships, had sex or even gotten engaged and started to talk about having kids..
I can't really accept my situation at the moment because I'm stressed and I don't really have enough money. In a way it's a bit like you, we both just want to be accepted.
Best of luck to you.