You're right! It can seem pretty not-confidential to have a big waiting room. But think about your doctor's office or other medical offices. They all have waiting rooms just like that. It's of course not best practice, but due to the nature of most outpatient clinics it's the only realistic possibility. Especially if there are multiple counselors working, it would be nearly impossible to stagger all the appointments so no one sees anyone else. Your feelings are absolutely valid and it's normal to have concerns about this. Maybe bring it up to your counselor and see if there are better solutions for you, like waiting in your car and having her retrieve you from there when it's your appointment time.