You have solved your own problem in the first sentence, even if you did not realize it. You will be fine, just take some steps to help yourself.
find it difficult to get a job and still not very clear on what I really want to do or should do as a career. I tend to lack self belief in this matter and afraid of social and appearance issues, which makes me avoid a lot of jobs too.
Because you do not know what you want to do, employers do not know what you want to do or can do either, so they do not hire you.
Because you lack self belief, and worry about appearance & how others will think of you in the job, you present an image of a person who is more worried about what their friends think about the job, when you should be trying to show an employer that you have the skill to do the job. This has led you to a place where you don't know what you what and because of that, have never learned any skills to show your value as an employee to a business.
You must make a decision to acquire basic skills to get a job. After you start working, go to a local school (trade, business, etc) and find what programs they have so you can advance yourself. The first courses are basic - language, math, etc so you have time to explore a career
while taking these courses. What so you like to do? Sew, decorate a room, work with children, design clothing, draw? All of these could lead to interesting careers - clothing design, interior decorator, teacher, jewelry designer, artist. You only need to sit & talk with someone at a school to assist you to focus and drect your talents.
All the best to you,
lady moon