Hey, Dude. Sounds like you're pondering the same things that all of us with depression have pondered many times. No, you're not a heap of garbage and you definitely have a purpose here. There is also a purpose for what you are going through. You are in the cocoon stage. When you have learned all you need to learn about this illness, when you've overcome some obstacles, when the seeds of courage and strength have emerged and grown, your "butterfly" will emerge in all it's glory. For now, know that Depression is a LIAR. It makes you believe the worst of yourself and skewes your perception about almost everything. Hang in there. You're accepted and understood here.
Take care of YOU.
<font color=blue>"Our doubts are traitors and make us lose the good we oft might win by fearing to attempt" --Shakespeare</font color=blue>
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Psalm 119:105 Thy word is a lamp unto my feet, and a light unto my path.