I'm not quite sure how you can call yourself the only introvert in the class. Unless you know everyone on a personal level, which most introverts don't, you don't really know just how people are on the inside. A lot of my classmates would think I'm funny and 'happy' a lot of the time, although I tend to be quiet in class. What they don't know is that I'm a really introverted and, depressed (there I said it), on the inside. They don't know my life story, the things that have happened, the things I'm going through right now, my social anxiety, and how it all affects me. They know what they see on the outside. I'm not saying you should know everyone that extensively, just don't assume that you're the only _________ because I can assure you that there's more than just you.