hot 13 year olds

A fantasy novel where a young depressed man decides to part away from the world. Unfortunately fate played a joke and instead of death, his soul was transferred to another world. He rejoiced thinking that his family will not be burdened by him but one day a voice said "Reach the peak of the world to return back to your real world." Then an image of his family members who were in hospital was shown. Again a voice was heard "The Catastrophe will soon befall Earth. Remaining days 24. Seeing that he gritted his teeth and decided to return back to his world. After countless years of struggle he finally succeeded in returning back to his world. It had been 9999 years for him but only an year has passed in the real world. Now his adventure begins. His lover who never responded to him was living with his family taking care of him. He knew most of the things as he got to view the real world once every thousand years.