You asked to speak to the teacher and were told no, wait for parents' evening? That's unacceptable.
I'm not in favour overall of meetings where children are present (as a parent or as a primary teacher), even at secondary level. Sometimes there are just conversations you need to have about your children that they are better off not hearing. At the primary where I teach, we used to have children along years ago, but ditched the idea in the end, as it was proving unpopular all-round. If, however, a parent wanted to speak to me at our weekly class surgery about a specific issue and wanted the child along, of course that would be OK.
For the record, we are having major issues with our Year 4s at the moment (particularly the girls) re: friendship groups, crises of confidence, imagined ailments/injuries and so forth. Barely a session goes by without someone crying about something. We have loads of procedures in place to help them (worry boxes/pastoral support worker/sympathetic TA always available/playground buddies/peer-group mediators/buddy benches/class surgery/circle time and so forth), but someone pointed out today that that might actually be exacerbating the problem in a bizarre way. Not sure about that, but they certainly seem very sensitive at the moment for sure.
Your school are out-of-line in not giving you an opportunity to discuss this. Parents' evening ought to be more about their academic progress, so they ought also to allow you a platform for talking about other anxieties.