I'm glad you were able to talk more honestly with your LCM about the sui thoughts...
I think having her go with you to the appointment would also be a good idea. You can both talk to the Dr. before the appointment and express your concerns over the exam portion. Most Dr's are ok going slow and keeping it all at a pace you can handle. I have lots of trouble with gyn exams, but my current dr. is awesome. Despite having seen her for the last 5 years, she still talks to me for quite a while before each exam. We catch up and she makes me feel comfortable. We re-visit what is helpful for me should I get triggered at all during the exam. She reminds me what she will be doing each time before the exam, but then we try to keep talking about random stuff while she's actually doing it (I find this level of distraction works best for me. Other people prefer to have the dr tell them everything they are doing as they do it). She checks in with me regularly during the exam, asking how I'm doing and if she needs to stop or switch things up. We've agreed that if I check out on her (drift off in the conversation or stop responding to her all together), she needs to pause to get me back, but then we continue the exam because having to come back again would be more stressful...
It may be a bit of a search to find a dr you are comfortable with, but it definitely helps. If you can have an up-front and honest coversation with them about your past, your discomfort with the idea of an exam, and any responses you can picture yourself having, it should go a bit smoother. And don't worry about leaving if you feel uncomfortable once you meet the dr. I know many are willing to meet before the initial exam, but some are not. If you can get a sense of how comfortable you are with them, it might help.

Good luck. Hope you can get checked out and the pain is nothing serious.