Thanks for asking your question. I'm happy to help.
From what you've said in your message, it does sound like you might be suffering from a depressive disorder
. Although we cannot provide a diagnosis without an in-person evaluation, it's important that you consult a licensed mental health professional, psychiatrist or at the very least, your GP to obtain a proper diagnosis and to discuss treatment options. If you've suffered social anxiety in the past and you feel that it's returned now, you might benefit from a specific form of therapy known as cognitive-behavioral therapy (or CBT). This type of treatment is very effective for anxiety disorders and depression. It's usually short-term and geared towards changing dysfunctional, negative and/or unrealistic thought patterns that can trigger or exacerbate anxiety and depression.
You can read more about CBT here:
And you can find a qualified therapist here:
Based on what you've said, it sounds like this could be a very beneficial option for you, especially since you say that you feel like you have no self-confidence and are over-analyzing other people's actions (this is a sign of a dysfunctional thought pattern, so CBT can help you identify the underlying thoughts and make positive changes so you can think along a more realistic and positive line, which can, in the end, help you feel better.) It's also possible (though it's not always necessary) that medication can offer some benefit (such as an anti-depressant or anti-anxiety medication), but you'd need to speak to your doctor about that to see if it's appropriate in your case.
There are some self-help steps you can take as well. You might be interested in reading this information from the Mayo Clinic to see if any of these tips are useful for you.
The first article is with regards to depression:
and the second is with regards to social anxiety:
I hope that helps. Please let me know if you need additional assistance.