I would suggest that you see a regular doctor first (or a psychiatrist) and explain the problems you are having. They could prescribe you a sedative to take before you go. Some people have to do this to go to a dentist so it's not out of the norm.

I have been having this exam for many, many years. I still am not comfortable with having one. You are right it is humiliating, but it is important for your health. Explain your situation before hand. Let the doctor know that you have not been with a man. They have a smaller set of tools that they can use, so ask. My daughter told me about this as she was having trouble and the doctor switched tools. I can't say that it doesn't hurt because everyone is different. I would call it an uncomfortable experience rather than painful. I hope this somehow helps, even though, nothing really helps with that feeling of being invaded, but you mom is right it is an important test. I don't like having a colonoscopy but I have to have them every 5 years to check for colon cancer as I've had precancerous polyps in the past. It is just something I have to do for my health.