Is there a way to be diagnosed for mental illnesses by a doctor without them telling my family members about them?

Yes: Most certainly if you are an adult...If you tell your doc that you want confidentiality, he/she must respect and follow your wishes...As long as you are not gravely disabled, a danger to yourself, or a danger to others. But...It is also usually in your best treatment interest to have as much support for diagnosis and treatment as possible. Families are often excelle sources of support/treatment.

Mental illness: Its possible to talk to a psychiatrist you are 22 and can consent for your treatment.The family history is important to gather info to come up with diagnosis and treatment recommendations.I would recommend not be hesitant if need good help have to provide all that is happening and relevant. Its never a good idea to hide info when seeking treatment as it can be damaging.Relax and be your self.