Please reach out for help from your parents as soon as possible. Ask them to take you to a psychotherapist or psychiatrist to get a mental health evaluation. Though I can’t diagnose you without seeing you in person, I can tell you that what you are describing sounds to me like depression — the empty feeling, the extreme irritability, and the difficulty finding a reason to live, social withdrawal, and negativity. The good news is that there are several very effective treatments for depression, including cognitive behavioral therapy, psychodynamic therapy, and medication treatment. If your parents have generally been supportive of you in the past, they will likely respond positively to your request for help. If for some reason they aren’t supportive, please reach out to another adult, like a school counselor, for help. You don’t have to live the rest of your life with this much emptiness and disconnection.
Take good care of yourself.