Harry Potter has what?!

what happens to Harry when everyone who was at Hogwarts or supposed to be at Hogwarts when the war started? Harry returns to school but he can barely breathe. He had barely been able to breathe during the summer. What happened to him? Why wasn't he visiting the doctor? What happens when his 2nd worst enemy finds him barely breathing in front of the great hall. This a fanfiction of doctor who and harry potter. Beware mentions abuse