After neutering a cat

Today I took my 8 month siamese male cat to the hospital to get him neutered because I felt this was not good for him anymore. Constant bitting, agressiveness to get out of the house, furniture scratching, spraying all over the place, even in my closet. What a little schmuck! The doctors inspected me that its better not to give him any food because he has to recover after anestyhia. First when I took him home, he was exploring the place like he's never seen it before and he was walking like drunk. Since he hasn't had food since yesterday, I decided to give a little of that gravy meal. I guess he got some boost of energy bc he became very playful. But still he is acting weird, like his soul has been taken out. Hes not emotional and cuddly as he usually is and its making me upset because thats why i felt in love with him in the first place 😢 I hope this is just how he is for today. Anyone had any experience with neutered cat and can tell me what I should be expecting after this? Any tips to make him feel better...? :/

He'll just have to get that out of his system. I imagine the no food rule is so they don't aspirate on their own vomit. But I had every male cat I've owned neutered. He should be back to his old spunky self in no time. It changed their behavior but little. Just curbed the spraying in my opinion. Didn't sway their wanderlust or any of that. Also cured them singing sultry blues outside of a lady cats house. Bonus.

He should be okay in a day or two.

Awwwww😢 I want to get a kitten and I would hate to have them fixed but everybody tells me its the best thing to do.

Non profit meaning what?