Drinking for many people, sounds like it may be true for you, numbs you out so you don't feel what's painful in your life. Stop drinking, and the painfulness of events and experiences comes back. Coping with drinking can be an excellent short term strategy to get some distance from the pain, but of course not dealing with the pain and whatever preceded it will always come back around and kick you in the teeth. It is hard.

Does the distinction between guilt (for something you did) and shame (for something you are) help you in any way? I think you can clearly put this in the guilt column, not the shame column. There is no fundamental flaw in your personhood that caused you to drive by her house; it means nothing about the kind of person you are or even the kind of client you are. Actions have consequences, people have reactions to what we say and do and none of it is under our control. And IIRC you have seen her since then, because you are or were seeing a dietician at her practice, and she didn run away screaming "911" when she saw you.

It seems to me that the grief and loss of that relationship is bound to continue to have its effects on you, because grief and loss are big. Shame is big too, and pretty sticky, but it may serve to protect you from the terrible loss you feel. For me peeling back the shame left another wound exposed and raw. For now, shame may be your friend.

I also think self compassion is appropriate here. However you want to define your part in what ended your therapy, giving yourself a break from being perfect and human is always appropriate. Understanding why you'd make such a choice and taking ownership of it, in my experience, helps in this endeavor. If you're someone who tries to do the right thing in your life, it can be tough to acknowledge a situation where that didn't happen. Doesn't mean you're not a good person. Saddle up and get working on the next right thing. Like keeping your sobriety (congratulations, well done!).