Other people may misinterpret my "calming my mind"
There is a difference between getting wildly emotional at every little thing and having empathy for others. I don't know your friend, or how you interact with her, but I can imagine she may have told you something that was emotional for her and your reaction was deadpan. 

This is not kind. It communicates to another person that their life and suffering is unimportant to you and breaks any social bonds you might have with that person.

It sounds like you are so attached to unattachment that you don't consider how your actions may affect others around you. You can stop people from thinking "something is wrong with you" by forming deep connection with people and showing genuine caring kindness for them.