I need practical advice:

I am due for a doc visit a very necessary exam. The very thought of it is sending my anxiety through the rough which of course causes my depression to spiral. This is due to a medical trauma I experienced last year that left me with PTSD.

For those of you that are willing to share: how do you broach this subject with your medical professional prior to the appointment? how do you get through the exam? How do you recover after? How do you stop yourself from freaking out ahead of time? Any other words of wisdom?
It is my first exam of this type since my trauma and every time I think about I have to practice relaxation exercises to not have a full scale panic attack.

Thank you so much in advance, any advice, love, hugs would be appreciated. I am terrified.