Honestly, I wouldn't be comfortable with a master's level therapist diagnosing something as complicated as bipolar or schizophrenia or autism, etc., especially without a second opinion. Even my pdoc is careful enough with diagnosing that he gets several opinions before completely "trusts" his own. In my case, he was right according to the other pdocs and therapists who gave second opinions, but he knows enough to know that diagnoses of mental illness is very subjective and deserves the time and care to be assessed carefully.

How about getting further testing, opinions, to help verify? It might be a good idea.