You are very critical of yourself. You are effectively blaming yourself for the misery you have endured and continue to endure. You seem to have adopted the “pull yourself up by your bootstraps” mentality. In other words, you might subscribe to the notion that if you cannot fix your problems on your own, then you are a failure.
Nothing could be further from the truth. No one chooses to be depressed, just like no one chooses to be diabetic. Depression happens to people. You’re not to blame, nor is it within your expertise as a layperson to know how to cure depression. Professional help is required.
You also described “paranoia” but I might categorize this as your inability to trust others. Your inability to trust can significantly affect the development of healthy relationships. That might explain why you have difficulty developing friendships. Some researchers believe that trust issues stem from disrupted early childhood experiences. Once an individual becomes aware of potential trust issues, they are correctable with therapy.
The reality is that these issues have plagued you since adolescence and perhaps earlier. They have never been brought to the attention of a mental health professional and thus you have never had the opportunity to make a positive change.
My recommendation is to seek an evaluation from a mental health professional. Many people have struggled with the same issues and with the right help, they have improved their lives significantly. If you are willing to seek professional help, you can expect a similar, positive outcome. Consider my advice. Please take care.