hi my cat is 7years old and was a very happy and active. About 2 days ago he started to walk weird I brought him to the vet yesterday and they did some test no no sighs oh kidney or urinary track problems. now he cant even get into his littler box and falls down when he gets up. the vet did say it looks like he has no pain but don't know what wrong and they have not seen this before. has anyone seen this before please help