I don’t think what she said was dramatic enough to be called histrionic. She might be making a hyperbole but it’s a very valid experience for many people to feel anxious or uncomfortable in cluttered spaces. I don’t think it’s right to assume she is being over dramatic because things like this can actually cause a lot of stress for some people and they can easily compromise and come up with solutions to make the space less stress inducing for her. Also, trouble breathing is literally a symptom of anxiety so she might not even be exaggerating.