I can see where you are coming from OP, and don't really agree with the posters who say you 'just' need to work on your self esteem.
It's not always that simple. When you have low self esteem, trying to build it is really hard. And sometimes the environment we are in is really damaging and takes all the energy we have.
I am from a working class background and from a very rural area. Despite conventional good looks (just averagely slim and pretty, nothing amazingly beautiful or anything) and a decent education, when I have had 'good' jobs, I have felt really out of place. Everyone else seems to be so much more polished, knows everything, speaks nicely and it leaves you feeling bad. It's like you spend so much energy just trying to not feel like a failure and trying to feel good enough that there's not much left for anything else.
I think when people say BUT YOU JUST ARE GOOD ENOUGH, their heart is in the right place, but also, they are refusing to acknowledge your feelings, because those feelings are not pleasant to confront. It is not nice to think that we live in a society where, actually, we ARE forced into little boxes, we ARE made to feel less because of our background/looks/education, and, no, not every story is a triumph over adversity.
I used to put so much pressure on myself. I used to want to reach the same standard as my peers who came from richer backgrounds, who'd lived in London/Glasgow/wherever their whole lives, and just seemed to understand everything and know everyone. And I realised that, no, career-wise, I cannot compete with them. I will never be able to.
So, I gave up my desired career in media and now I'm a teacher and I feel happier. That's all that matters. I focus on my hobbies and my friends, and yes, I would prefer to work in media, but why push push push for something that is not within my grasp?
We are fed this idea that we have to pursue our dreams, but it makes us so unhappy sometimes.
So. I get where you're coming from.