I've been the type of loner who is a loner in crowds, but you'd never know it. I'm a loner, and sometimes I tend to distance myself from my friends. I use my mind to get away, and then I become distant.
I am the same way. I love your picture by the way. I love going for long walks and looking and thinking about nature.
You said, you escape into your mind? What is it that your escaping to? What are your thoughts/dreams? Is it a happy place? What can your mind give you, the world around you can't?
I got to say, even so I prever being alone, compared to 'socializing' ...lonleyness is fairly hurt full sometimes...