Maybe because it's you who has given up on life. Maybe you just can't see the purpose of living, but that doesn't mean that there is something in life that you enjoy. I'm no pro at life myself, but life gives you a meaning to live. I mean, what is the use of you waking up everyday, just to feel like you have no means of wanting to live any more when there are people who are dying, and would love to live. Zero energy may be the cause of you, like I said, giving up on life. Unless it has something to do with medical reasons then the best bet is to not let that get in the way of you living a happy life. Trust me, life ain't always easy. Then again, life never was, it just makes you who you are, and what you'll become. Cherish your life, regret nothing.
