I'm not sure anyone in the world cares about my existence. I'm at my lowest point in life and no one around me knows
Sure people care! Did you tell them about this?  What are you doing about getting out of this depression.
I'm trying to get stronger each day and not get killed by depression
If you hide your problems from people, you can't pull yourself out of your tailspin even if you are working on getting stronger. Rely upon others to help you through this difficult time.
I'm taking control of my life and it's my business. I don't really like your advice and also I just need to somehow survive
I'm telling you other people can help you get through this alive. Please let at least one close family member or friend know what's going on so they can help you. You really don't want to fight this alone.