I too have high functioning depression. Mine usually starts out with anxiety and it gets more sever if not helped and then the depression comes. I am scared and anxious about disappointing people. Like my boss and parents. When I do get into a depressed state I hide it from everyone so I can continue to try and make them happy. Good employee/daughter. Then the minute I'm alone I sob and self hate and pick on everything I've done wrong in my life. The stress of trying to be perfect is what makes me both high functioning but also depressed. For me it is a vicious cycle. But I hope you find comfort knowing your not alone.