Welcome to the forum Green,
I was in the same position as you 4 years ago.
The therapist I was seeing at the time and still seeing by the way, suggested I start journaling and bring the journal into session with me.
This works very well. Gave the therapist a place to start talking, gently and would ask if I was ready, some times he would keep the journal for a week to read the whole thing if I agreed, so you can you loose paper if you want.
Eventually, I started to
open up, there are still things I don't tell him yet, but will I am sure.
Feeling better after your appointment, will take some time. It is a work in progress.
We have a 'resource' thread at the top of forum. PLEASE review these pages, there is alot of helpful information you can use to stay safe and strong until you find a therapist that fits you. www.goodtherapy.org/therapy-for-ptsd.html#
This link is additional help for you, if you live in the United States.
Peace and strength