My adult (2 years) cat has developed a fear of outside, and other funny behavior. She cries when alone, sometimes, and often stares in space, or at something "not there". She will NOT go outside with my two other cats, unless I or my roommate is with her. This has happened in the last three months. Is there a tranquilizer for cats? I am very serious. I have tried the infuser with Feliway, calming treats, etc.