In my amateur knowledge, I understand:
. Accepting expensive gifts is contrary to their ethics.
. Likewise entering into dual relationships, of which traveling to officiate at your wedding certainly qualifies. (mazel tov, by the way.)
. The payment plan needs to be clear, written and understood,and not because "she loves you."
. Your sessions should be for your benefit. Argument: "I don't work for free" and "where's my money" doesn't pertain to your mental health.
. She needs written consent to talk with other providers.
. I know nothing about medication beyond there's a protocol for withdrawal for many medications. Holding needed medications "hostage" sounds out of bounds.
. On your end, you owe her money for services.

It's a business relationship bounded by strict guidelines.

I'll speculate that your failure to make repayment your priority is a strong factor in this recent deterioration of your relationship. That said, she never should have allowed such a loose relationship from the onset. The problems you face now is why it's unethical.

A once-ethical provider or a relationship can go out of bounds at any time. Sounds like you've recognized this and have taken steps to get away from her.

For more information, you can contact TELL: Therapy Exploitation Link Line