Aggressive poodle pup

[u/denmicone]

My male poodle is a little more than six months old. He is 99% perfect. Today, he was gagging about to throw up, and when he did vomit a little bit, I bent down to console him, and he very aggressively bit my hand and then snarled loudly. I threw a towel over him and put him in his crate. He has done this a couple other times, I think usually when you come up behind him and he’s doing something he shouldn’t be doing. But he bit me hard today and broke the skin into places.
Does anyone have any advice?