Yes, I'm with salukigirl and would take the cat to a vet to be checked out. My cat kept bugging me all night (and finally peed on us) and had a serious illness that needed daily pills.

They can't talk, so often it's the only way they can get your attention. I'd take the item of clothes into the vets after you've cleaned it and ask the receptionist/tech if they can smell it for you :-) and suggest ways to clean it better? Surely they know about animal pee :-)