All of the issues with which you are struggling can be remedied with therapy. Your parents isolated themselves and this prohibited you from developing a healthy interaction style. The thought of interacting with others invokes nervousness and thus you avoid it.
As a child you had little say over what your parents did and did not do. They chose to isolate and unfortunately this negatively affected you but as an adult you can correct it. Dealing with nervousness, learning new patterns of interaction and so forth, are skills that can be learned. Therapy could greatly assist with the development of these skills.
As you stated, you feel completely helpless. You have tried all that you know to correct these issues but you have come to the point where you no longer know what to do. Mental health professionals specialize in teaching people the skills that you are interested in learning. It makes perfect sense that you would consider therapy at this point your life. It is the way to “turn your life around.” Please take care.