M.P.
I agree that you're misreading the doctor and nurse. For some reason you're expecting them to not take you seriously. Perhaps because your family doesn't. I suggest that when you start to think that the doctor and nurse are doing these things you stop yourself and tell your self that they are professional people who do care about your well being. Be doing this you can change the way that you think and feel.
Think about how he's referring you to a urologist is taking you seriously. He's honest and says he doesn't know what is causing your symptoms. That doesn't mean that he doesn't believe you. It only means he doesn't know. A doctor told me once that not knowing why I was in so much pain only indicated that that it would take more time to figure it out in response to my question asking him point blank if my pain was psychosomatic. I have endometriosis. It took many years to know that. During those years I had tests and eventually surgery. It was only persistence over time that gave me an answer.
Also consider that the nurse was smiling in sympathy not smirking. Or that she's new and was smiling because she's uncomfortable. Give people the benefit of the doubt.
What is most important is that you call now and make that appointment. What does it matter what the doctor and nurse think. What matters is that you have pain and the urologist is the next step in learning what is causing the pain. Do not get side tracked with your anxiety and fear over what the doctor thinks.
If you can't shake the feeling that the doctor and nurse aren't taking you seriously, try some counseling to find out why you're prone to expecting the worst and a way to change the way you think. As I typed this it clicked for me that you learned this way of thinking from your family. You said that they're prone to think the worst. You're doing the same thing with the doctor.