Have A Problem With My Exotic Cat Had An Extension

Have a problem with my exotic cat had an extension built and our highly strung cat seemed to tolerate it week after it finished we gave our cat who is an indoor cat his usual flea treatment advocate and he went completely mental and has gone into hiding flicking his back, ears and tail and does nothing but retreat to his bed only coming out to use his litter tray seems to be completed depressed been to our vet he is healthy has had blood tests and everything was fine but he is still in hiding and is throwing up on a quite regular basis