I’m sorry the therapist wasn’t more deft in keeping your mother engaged in therapy. But it may be that nothing a therapist can say or do will help her feel like family work is needed or worthwhile. That being said, it’s time to stop blaming your mother for her overprotection and take charge of your own life. You can’t change your mom. You can change how you manage your life and how you interact with others.
Social anxiety is difficult, but it is not impossible. A place to start helping yourself is at your local or school library. By studying there, you will minimize contact with your mom. By looking at books on anxiety disorders, you can develop a self-created treatment plan. You can also go to a book seller online and find a number of workbooks that provide step by step strategies for becoming more comfortable in the social world. Working through some of those workbooks is likely to be helpful.
In addition, I encourage you to join one of the forums here at PsychCentral. You will meet people online who can give you practical help and support while you work on taking better care of yourself.
Yes, healing will take work. But staying isolated in your fear isn’t going to help you make friends or get on with life. You are smart enough to be in college so I think you are smart enough to read and benefit from books and to successfully utilize online support.
I wish you well.