Hello and a warm welcome to PC.

You are far from worthless or a waste of air. I’m sorry you’ve been struggling so much for so long. Please seek out help. The answer for you might be around the corner just out of sight. You might benefit from talk therapy (a psychologist) or medication (a psychiatrist) or a combination of both.
Hang in there. There is hope! Please keep posting and let us know how you are doing.