That seems to me anxiety is hitting you and you don't even know it.

Years ago I used to often verbalize things I wasn't supposed to, and now I understand it was all due to my anxiety. I was always shy and awkward when socializing and dealing with people, and was never the most popular or smartest person around, so I'd often make a fool of myself when trying to fit in. Oh the memories of stupid things I said still makes me hurt inside...

I'm also a slow thinker; compared to other people it normally takes me a lot longer to "connect the dots" and, fearing I'd lag behind in the conversation, I'd just dish out half-baked thoughts that would make me look like anything but smart...

What "cured" me was that I used those traumatic experiences to remind myself to keep my mouth shut next time. Gradually, I learned to think before opening my mouth (though this doesn't seem to work very well for typing on Internet forums...).

The side-effect of that approach is that I've become more isolated, more introverted. Maybe the reason why I was always so goofy when speaking to people, is that I was (unconciously) trying to be the person I wasn't meant to be.

Well, I hope that what I wrote helps somehow.