I think that you may have correctly identified yourself as suffering from social anxiety disorder, or at least some form of anxiety. I can’t know this for certain, of course, based on a short letter over the Internet, but a diagnosis of anxiety (some form of) does seem to fit. If you wanted to verify whether or not you have a social anxiety disorder, then it’s best to meet with a mental health professional for an evaluation.
What is good about your question is that you expressed a desire “to come out of this hole, or shell, and start living my life.” This shows that you recognize you have a problem which needs to be addressed and it also indicates that you may possess the motivation to improve your current life circumstances. These are the first steps to improving your life: knowing that there is a problem and showing a willingness to make an effort to correct it. In this respect, you have already taken your “first steps” to correcting the issue. In my experience, people who strongly desire to change and are motivated to do so usually have the most success in making the needed changes in their lives.
I would suggest that you make an appointment with a mental health professional, preferably with a therapist who has experience working with individuals who have anxiety disorders. When choosing a therapist, you want to select someone who you like and feel comfortable with as well as someone who has been highly recommended. You may also want to choose a therapist who works closely with a psychiatrist. I make this suggestion because some individuals with anxiety disorders benefit from medication when they are first learning more effective ways to socialize. Medication can help you to feel less nervous in social situations. You may not need the medication for long or you may not need it at all but it might be useful to you. You and your therapist can make this assessment when the two of you meet and discuss your anxiety condition. Thanks for writing. I wish you luck.