I empathize. I need to get a gynecological check and mammogram; I keep putting it off. I have been in your shoes. I AM in your shoes, except it's not my first exam.
That said, I was also a nurse. Sadly, sexual abuse/assault/rape/trauma is something many patients have experienced. Many doctors and nurses are fellow survivors. Most doctors, especially OB/GYNs, have a place on their intake form/history to circle sexual abuse and mental health problems. If you have been diagnosed with PTSD or anxiety, please put it on your form. You can call and ask for a consult where you can stay fully dressed/not have a gynecological exam on your first visit. This would allow you to share your history and concerns and gauge their response. Some places will prescribe an anti-anxiety med to take before your appointment (if that isn't triggering) for the gynecological exam. Do you have a friend or family member you would feel more comfortable with having them in the room? I have had a friend, my (ex) husband, and mom present during an exam.
Most places have a second person in the room. They usually help with prep and passing tools, BUT they can also hold your hand. I have done this for many patients. I would remind you to try to stay calm, to take deep breaths, and to wiggle your toes if you started to tense up. This can help your vagina relax. With survivors especially I tried to empower them. Ask if there is something that would be helpful to say/not say. Some survivors like to be distracted. If you seemed really nerved up/tense, the nurse or doctor might ask you questions about your life, hobbies, school, a pet, etc. We are their to help you be as comfortable as possible. Given your history, the fact it's your first exam and you are being seen for pain, they should be compassionate. The doctor (should) tell you about what to expect and guide you through the exam, telling you what they will do next. It's a common technique for the doctor to touch your leg first. If you are not relaxing enough they may tell you to relax and try to gently guide you into position. This is a COMMON practice. They shouldn't "push" per se but guide. If you feel they are "pushing you"/being pushy, remember YOU are in control. Consent type language may be used, saying for example, next I will put in the speculum. Are you ready? You CAN stop the exam at any point..."for a second" to give you a chance to take a deep breath or move your legs as into the necessary position. If they know your history in advance they can schedule you for a longer appointment time. If for some reason you just cannot finish, you can end the exam. If you are afraid of freezing up/not being able to speak up, set a hand signal. They aren't trying to do this TO you. They are trying to work WITH you to find out what's going on.
It's hard, but YOU CAN DO THIS!!
Sorry this reads like a mess. It's in the middle of the night.