I agree with others that conferences often are not the best time to ask for an in depth conversation with the teacher. Our conferences tend to be jam packed with data that the teachers are required to share. There usually is no time to talk before the teacher needs to move on to the next family.
I get the impression that you still would like to talk to the teacher. I would send her an email asking for a time to meet outside of conferences. I would list the points that you would like to cover in the email to give her time to process and come up with a response. You may want to say that you understand that things seem to be going well in class but want to make her aware that things at home may indicate your kid is stressed.
I also have kids who can hide when they are miserable. I've had more than one perplexed response when I've brought up that my kid came home in tears or didn't want to go to school. The good teachers want to know when the kids are burying stuff.
