Yes, the bed probably is too big. I think I start out drawing the area around Harry, then leave the rest as I fill in the background. Then finish the bed without taking into account that I haven't filled in enough space around it to keep it a smaller size. if that makes sense at all! I don't envision far enough ahead to properly draw it, sometimes.
I actually used reference for his head and neck... I don't think it is wrong, as he is looking downwards and holding his head back. Like, tilt your neck back, and yet still look down. Like leaning away from something without actually leaning. Do you know what I mean? That's what I was going for, perhaps it was an odd position to choose though. But it's entirely possible I didn't shade properly enough to depict it realistically. I drew it traditional and I was scared to ruin his face, so I avoided shading it.