some therapists have the credentials to do diagnostic evaluations. example many therapists are now licensed as Psychiatric Therapist. this is a therapist that has all the credentials/ degrees and have passed their state boards that gives them the ability to administer diagnostic evaluations for mental disorders, some are even able to prescribe medications now.

there are also many psychiatrists and psychologists that also do therapy services not just medications and diagnostic testing.

my suggestion again is if you dont agree with your diagnosis you can ask for an official diagnostic testing process with a psychiatrist or psychologist.