Hehe, flicking his heels means he is a little mad. Its nothing to be sad about, he is likely just unhappy about the surgery. As his pain and discomfort dies down, he will start to go back to his normal self
For some bunnies, this is a few days, for others this can take a month or so. But, he is letting you pet him so he is not mad at you at all, likely just mad at the situation
How is the wound looking today? For our cones to stay on, we use the top ring of a cut sock, or a thick hair scrunchy. Make sure if you use either of these that you test it out around your hand and wrist first. You dont want it to be tight around your wrist, and you want to be comfortable but slightly tight around the lower bit of your hand (depending on the size of your bunnies head and neck). Tight enough the bun cant pull it off, but loose enough that it doesnt choke the bun. For make shifts that only need to hold for an hour or two, ive used paper plates i turned into cones then cut off the pointed part to slide the buns head in 