Acid is the most clear-headed psych I have done, and what you describe sounds just like a low dose trip. Taking a low dose of acid on my first time had me questioning if it was acid or not as well. Taking double the dose on a later date assured me that what I had was acid =). If you are desiring "thoughts tumbling over thoughts", I would highly recommend shrooms! Every time I eat shrooms my mind just races like theres no tomorrow! <---This is the reason I do not plan on eating mushrooms anytime soon. OH and for teeth clenching, I too get this with acid sometimes. I think it is do to being stressed in a way, and I do not mean a bad stress; just from intensity of the trip. On a more relaxed trip I had a few weeks ago, I had no signs of the jaw tension.