It seems as though you have a fear of social rejection. It also seems as though you’re preoccupied with what others think of you. Those are some of the symptoms of avoidant personality disorder, but to know with certainty if you have that disorder or any disorder would require having a psychiatric evaluation.
It’s important to keep in mind that, generally speaking, we do not know what others think about us unless they tell us. We make assumptions and those assumptions may be wrong. Those assumptions are based on how we feel about ourselves.
For instance, an individual with depression likely doesn’t think highly of themselves. They assume others feel the same way. Other people may actually think very highly of them but their judgment is clouded by their depression. They may ultimately conclude that other people don’t think highly of them when in reality they have substituted their judgment for the judgment of others.
Like the person with depression, your assumptions may be incorrect. It is possible that people do not feel the way that you think they do.
Don’t assume that you know what other people think of you. Allow for the possibility that you could be wrong. If you have low self-esteem, then you are likely misjudging what others think about you. Also, realize that you cannot, no matter what you do, control what other people think of you.
It is clear that these problems are holding you back in life. My recommendation would be to seek therapy. Therapy would be advantageous for several reasons. Therapy could help you address your social anxiety issues, determine if you are correct in your assumption about others, and it could assist you in moving on with your life. I hope you consider it. Please take care.