I think that repeatedly pressuring your professor for a response after he had told you no, especially over the difference between an A and and A- may demonstrate poor boundaries and a lack of an ability to accept the answer, "no." In no way, do I see it as as proof you're not meant to be in graduate school or to become a therapist. Graduate school, especially to become a therapist, is about more than academic learning. It's about learning to navigate interpersonal relationships and to show that you can handle yourself under distress. While I was in school, the most difficult parts were the interpersonal relationships. I hope the referral is designed to help you and teach you so you can move forward successfully in the program. In my experience, it's never a good idea to call someone with power over you an a**hole. It's always come back to bite me.

Best of luck--Don't give up!