Possible Depersonalization Disorder, among other things

This is going to be a long read. But if you hear me out, I would appreciate it so very much. I don't have any idea what to do with myself.

Have you ever looked out of a car window, and taken notice as to how much duller the world looks through it? Imagine that the world is like that all of the time. Unable to properly touch the world outside. That's how I feel. As if my eyes were merely windows from which I view the world, and not my true eyes. My mind and body feel separate. As if I were only a brain connected to eyes riding in a soulless body. I feel as though I am moving outside of everyone else's timeline. This has been happening since the 6th grade, and I have recently been losing more and more of the ability to feel emotion. I have been depressed for the majority of my life, and when I got out of it, this condition became stronger. I'm not even sure if I am depressed now because I don't feel it. I'm numb, and no one knows about it. I missed my appointment with my therapist last week. I am almost fifteen, therefore I have no car. I just finished my Freshman year. I have my mother, step-father, and little sister. My real dad hated me.

On top of that, I feel like I'm getting dumber as well. Maybe it's just because I keep telling myself that I'm unintelligent and ignorant. In middle school, I was that really annoying kid that everyone hated. I've grown out of that, but now that I've thought about it, it makes me feel worse. I have a passion for music, technology and film, but I feel like I have no future. At the end of the year I noticed that people began to like me more, but I can't enjoy the thought on account of my emotionless husk of a person. My father, of course, never taught me social etiquette, and neither did my mother, so everything I do freaks people out or annoys them. I act so differently. I have a fear of judgement, and am very critical of myself. Any time I pick up on any behavior, I think "This isn't me. I shouldn't be doing that." As if who I am (or was) is locked down and frozen. Unchanging. I have no idea what is going on anymore. I feel very, very alone.

Also, I am an Atheist and therefore have no faith in a higher power. Just to avoid misunderstanding.

I really needed to get that out. Any help would be appreciated greatly.