"I DON'T CARE!" Harry yelled at them, snatching up a lunascop..." — J.K. Rowling quote meaning

I DON'T CARE!" Harry yelled at them, snatching up a lunascope and throwing it into the fireplace. "I'VE HAD ENOUGH, I'VE SEEN ENOUGH, I WANT OUT, I WANT IT TO END, I DON'T CARE ANYMORE!