I can't stop thinking as well. I never tried meditation, although I'm trying to "clear" my mind of all thoughts with no particular technique. Never works completely. Especially when falling asleep I'm thinking way too much - it's like Ne finally shuts up because of lack of external input, and Si jumps in to go over all the things in my mind, categorizing them and having Ti examine them from its point of view. I fall asleep I'm too tired to stay awake.
Sometimes I feel I'm thinking less than usual when busy with conversation, but I fight this, despising not being in control of what I actually say and do. I mean it's not really like I'm saying things without thinking, but it's somehow diminished.