How do I calm my very badly behaved two year old?

He never listens and does what he wants. He stays up all day and all night. I him when he does something absolutely terrible. But he still does it anyways. I talk to him kindly and ask nicely but he thinks I don't mean it. Even when I get angry and raise my voice at him. I put him in time out but it doesn't seem to work. I play with him when he plays with his toys, when we go to the park, he has so much energy and is always hyper. I am in denial that it's a medical condition as well as misbehaving. What should I do? He's so bad that it makes me feel like a failure as a mother. And makes me feel like I want to give up on him. Which breaks my heart.