Generally in graduate school professors aren't going to go over each deduction with you like many professors will with undergraduates. In graduate school, they are teaching you to be a scholar and practitioner in your own right; if points are deducted, you are expected to have the ability to reread your work and figure out what could be better. It is acceptable to make an appointment during office hours and discuss what you think the weak points were, after you have done that.

The email exchange was disrespectful. An A- in graduate work is, as he told you repeatedly, a very good grade. Continuing to argue after he said he didn't think it was productive crossed a professional boundary. Apologizing and accepting feedback from your advisor and chair about how to handle these kinds of things in the future would probably go a long way to repairing your reputation as a student.

I'm sorry it's hard. Graduate school is grueling without the added burden of new medications and mental illness.