I do similarish work and have "service-orientated brain" and am probably annoying because of it, too.

When you're engrossed in that mindset for 40+ hours a week it can be hard to turn it off.

I think the solution is writing her a note and letting her know what kind of support you are looking for and that you aren't their client. Then talk to her about ways that you are wanting to communicate to her and ways that you'd like her to communicate with you. Let her know that you are not going to be upset if she goes into 'therapy brain' because you understand that it is her passion and acknowledge that she is good at her job when shes working but you want to build intimacy in your relationship and in order for that to happen she needs to let you in.

I think that writing out your feelings will be better than talking to her as she probably won't let you finish whatever you're saying. I feel like part of it is protection because when you do training for this kind of stuff in order to maintain 'professional boundaries' it requires you to divert from yourself to focus on the client.

I'm a blabber mouth though and kinda suck at professional boundaries sometimes HAHAHA. Luckily it's less important at my job because the requirements are not as demanding.