I have had this issue. Though, frankly speaking I just tend to mirror the way people are feeling around me in any given situation as to fit in when I myself might just be feeling nothing, which is actually most of the time, and in the end I'm not really affected by it. However, in the same manner I've had people call me out because they thought I was depressed when, again, I was feeling nothing. I've had everyone in my house hold, including my half-brothers, one day just starting to ask me if I was okay which struck me as odd at first until my father eventually filled me in on what everyone was thinking.
This however is a completely different issue. It annoys me that us introverts can seem depressed or anti-social because we like to spend time alone. Given my age (19) people usually just think of me that way because I'm supposedly in that time of my life where I'm meant to go out with friends and have 'fun'. Sadly the definition of 'fun' in a world dominated by extroversion isn't the same as my definition of fun and whenever I want to be left alone with my own thoughts I am pestered by people who don't seem to understand how I function. Apparently I'm expected to go out, and either get drunk with 'friends' or dance in nightclubs. Although I do enjoy alcohol I tend to moderate the amount I take in at any given moment because I simply enjoy being lucid. Now my main problem are the nightclubs that I'm supposed to go to. Not only is the music too loud and not a type of music I enjoy, it's too crowded and I just feel like I don't even fit in there. I'd much rather be doing something else.
Apparently some people think that not going out at night at all means you have no social life when I am quite content with the little social interactions I do have with my very small number of friends during day time. Others would say that what I just described would be cutting loose and that I am too reserved, but if it's not something I enjoy it is not cutting loose at least for me, again a stereotype enforced by a world dominated by extroversion. I am not implying that all people my age should be doing is going out clubbing by the way, but given the age of my half-brothers who are quite extroverted and spend all of their weekends going to parties(and trying to pull me along with them) it's what I'm pestered about the most and the example that came to mind the sooner. I actually spent about five minutes after writing the main chunk of text thinking about another example but eventually I just got tired and decided to move on to something else.