Irrational fear?

I'm 20 years old. I have never been to a gynecologist... and I have had menstrual issues since I've started my period since at 11 years old. I have been sexually active since a young age too. Going to see a regular doctor gives me anxiety, and I've been putting off seeing a gynecologist for a long time. I have an appointment in October. Ladies.. I am so scared... it's a woman's health exam, so they are doing it all. What can I expect? How do I calm down? I need some advice. I know the second I walk through those doors I'm going to be a train wreck. What is the process? What kind of things should I expect? Thank you ladies