Resource guarding or aggression?

Hi guys

So I’ve just had an incident with my 4 nearly 5 month old pup. He’s a big old dog already so Ngl it scared me a little bit. He was sitting next to me on the sofa, he was chewing my glove that I’d literally just put down (yep! I know. Rookie mistake) anyway, I went to retrieve said glove and he growled and went to bite my hand. This is my first dog so, as much as I’ve read as much information as I can, this is the first time I’ve experienced this behaviour. I thought resource guarding was for food?

I didn’t snatch it from him, i stroked his head and then said ‘leave’ & tried to retrieve it.

What did I do wrong?

Is this aggression or resource guarding?

Thanks guys