Hate to brake the news to you but all the things you mention as anti-social behavior are just kind of cat things! Lots of cats will only drink fresh water from the tap. Headless mice is their way of presenting you with a gift. Would you really expect the cat to pick dirty laundry to sleep on if clean is available? Wiping his feet and pushing on the cat door...so you will pay attention to him!? If he is sick, he can't stop to access the difficulty involved in cleaning the carpet. That wouldn't be cat-like at all!

The kitty obviously has a physical problem that will need to be addressed by someone with more knowledge than I. Just wanted to state that, while the "anti-social behavior" may be a change for him, it is all quite typical cat behavior (other than the vomiting, which he certainly can't help) and he has just been very well behaved prior to this! Perhaps as he started feeling ill, he started trying harder to gain attention.