I think your depressed. If you are in your teen years, there is always that hormonal change you must go through. It isn't your fault to feel this way. Another reason is kids have severe anxiety and it keeps them in their room. You must confront any fears you have. I am an anti pill anything, because doctors give them out like candy especially anti depressants, so I would recommend you joining a gym. Cardio works wonders for our brain as well as weight training. You don't need to speak to anyone, just exercise, which brings out good endorphins. Best of luck to you as you don't want to spend the best years in your room.....this happened to my brother and he listened.
I think that this is normal. We all go through periods like this from time to time.
You may be stressed (from the lack of face to face social interaction, humans are mostly gregarious creatures after all), and have started acting out through negative self-talk.
It may seem harmless enough, but say something often enough over a long enough period and eventually you'll brainwash yourself and start believing it and acting on it.
My suggestion: more face (to face) time, less electronic stimulation (iPod or whatever) time. Find someone to chum around with or hang with at school for example, weekends too if you can manage that. If nothing else, that will give you less opportunity to talk to yourself. I think it will likely shake you out of this current downward spiral.