Fuzzy I truly feel for you as I too suffer from constant yammering in my mind: Things I have to do, things I haven't done, continual negative criticisms of myself, and so forth.

One way I try to deal with this is with the yoga technique of focusing on my breath, narrowing my focus to that alone, and repeating some sort of mantra. This can be literally anything repetitive and neutral in feeling tone. In my case it's a brief series of words repeated over and over again. If I can succeed in this my focus will narrow enough to what I'm presently engaged in that the negative chatter begins to recede and I feel some relief.

It's the pits that negative self-talk endures long after the environment that led to it may be gone.

(((((( ))))))