I don't always feel like I'm in the drivers' seat.

I don’t really recall how long this has been going on, but every now and again, I feel like someone else is in charge of my voice. It usually happens as I’m getting more and more upset about something. Or, what may start out as playful teasing, I’ll somehow turn it into something serious, and that’s when I feel like I’m losing control. I want to shut up but I keep going and I almost always regret the things I say. It feels like I’m watching myself from over my shoulder, screaming at myself “enough!” but no voice comes out. Like I have a “Ms Hyde” in me, except not quite so evil. The whole while I’m ranting on about things I’m going to regret, I want to stop and shove my foot in my mouth, but I can’t. And that’s what scares me – I CAN’T. I know it should be about mind over matter, and if I think I can’t, then I won’t be able to… So how do I get around this self-fulfilling prophesy. And an even better question, why does this happen to me? What is that all about? Is there a name for it? I’ve already been on anti-depressants for about a year and a half now, though I’ve never told my doc about this in particular. Obviously, that would help but it feels weird in there. That makes me feel like I’m a specimen being observed. I’d rather this where I’m a faceless person asking for help. Is this related to depression? Do I have some alter-ego waiting to come out?! I’m really scared. Has this ever happened to any of you?