It's difficult to give you specific advise, as I have not evaluated you. But I can give general advise. If you have never had a job and barely passed high school due to your poor attendance, then your social anxiety may be quite severe. The first thing you need to do is to figure out the severity of your anxiety symptoms. Click here to find out your anxiety levels. After you find your anxiety levels, then you can then start on a treatment plan. If your anxiety levels to be very high, then you may need to visit your doctor to give you a full assessment and possibly prescribe you medications for anxiety. You will also need CBT (cognitive behavioral therapy) to address your irrational thoughts that lead to anxiety, and your compensatory avoidant behaviors which maintain your negative cycle of anxiety.
After you receive treatment for your social phobia, then you can use the skills you learned in therapy to apply for jobs and eventually to go on job interviews. You can't really make decisions on jobs until you get a handle on your social anxiety.
