Your fears are normal, but also unfounded.

Think of yourself with a business to run (your self) and think of the therapist as someone you hire as a consultant. Now, if you had a regular business, you would call your consultant in each week and discuss what the best course of action would be for a particular issue you saw with the business, right? That's how to think of therapy: your T is a consultant you pay to help see things you might not realize, and to offer solutions for those issues.

Make the call. You don't have to know how to do this, that one of the reasons therapists are trained, so they do know how to do this. When you make the call, and if you leave a message, say that you really want to do this but need her to call you and help you make an appointment. That gives her permission to contact you more than just a polite return of your call.

You can do this.