I think you're taking about desensitization. If you're paying for individual therapy, they should be helping you with just the situations you mention. You can have therapy anywhere. In therapy, you can practice calling restaurants to ask questions, calling the registrar at your school, calling Netflix to ask about plans, whatever. You can go to a coffee shop/restaurant/grocery store with your speech therapist. Another thing to consider is Delayed Auditory Feedback. It's not for everyone, but I believe there are apps that are free or cheap to try. For some people, it fixes fluency when it is on.