Don't take your GP's response personally. She is referring you on because she feels someone else's input will be of more benefit than she can provide right now. She has your best interest at heart. She is not having the secretary relay messages to you because she does not care about your suffering. She is having the nurse perform this task so she can treat the other patients she *also* cares about.
I say this because I know the other side as a medical provider. That said, I COMPLETELY understand how you feel. As a patient I way overthink and worry about my doctors responses or actions. The biggest reason why I ended up getting a psychiatry referral? Well, part of it was that I wasn't getting any better after a few months of treatment with my family physician. But the MAIN reason was because she's a colleague,works part time at the same office I'm at and I worried too much about what she must be thinking about me....yeah, that's not conducive to anxiety treatment. I still see her for my other medical concerns, but not the anxiety.