First post on this forum. I'll probably make a few more... I guess I could only say that I worry about myself sometimes. I don't know where else to ask this, so I'll ask here.

I'm going into my senior year in high school, and I started this nervous habit when I was fairly young. Maybe 11 or 12. Whenever the thought of suicide or self harm would pop into my mind, I'd blurt out something about killing someone else. As I got older, the problem got worse. The more I think about killing myself, the more I start blurting out random things and talking to myself. I normally say very violent things out of context. In the past couple of years, my short phrases have turned into conversations. I'll just start yelling about how I plan to kill someone, how I'm already dead, or how I plan on quitting school and work. The only thing is that I'm having conversations with no one. My mother asks me if I hear voices and then respond to them, but I don't hear anything. I just get overcome by this feeling and I start talking, and I have to force myself to stop. I tend to yell at home, and then speak at a normal tone or whisper in public. Is that normal? Or what could cause it? I guess it's just a nervous habit, but I don't know how to knock it off.