My cat just got neutered he's acting nuts is this normal...?

I'm not sure what anesthetics your vet used, but chances are it was the drugs. Every animal burns off the various anesthetics/gesics at different times. He was probably still a little tipsy from the surgery. Is he on pain medication? They can be narcotics and obviously cause a change in behavior while helping with post surgical pain. Your vet should have really gone over all this with you when you picked him up after surgery. If he is still acting odd, I would give your vet a call and let them know what is going on. At least get some answers.