Why do I feel tired all the time, and why I can't even seem to be able to think clearly?

I know I have been depressed. But could this be the reason for my tiredness?

Please help.
Update: I am depressed because i haven't achieved anything for my age, and I see people around me, my age, having achieved.

Also, I have a "sadist" sibling who takes joy in hurting me and keeping me from growing by "heterosuggestion"
Update 2: he intentionally discourages me, uses words like a master "discourager"
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