There's a subtle trap in trying to stop compulsive thought; which is that it can easily lead to too much thinking.
You have to realize that you cannot stop it by catching it one thought at a time any more than you can stop rain with a bucket. Your bucket will fill up with water, but you'll never catch all the rain. It sounds like you're watching yourself holding a full bucket and wondering why you're still getting wet.
Affirmation, "The Work," the Sedona Method -- all of these are thought structures. So you're replacing one thought structure with another. That can have useful benefits. They're good at helping to release pent-up emotions; but they won't eliminate compulsive thinking.
If you want to make ground against an overactive mind, you have to teach it to sit quietly. And you do that by practice. That means meditate; empty mind, full awareness. When thought arises, observe it as something separate from you. If you do that, it will dissipate. If it does not disspate, you have not done that. Start with 10-15 minutes a day, every day. Work up from there. An hour a day is a common recommendation. After a while, you'll notice your quiet mind will show itself during normal activity.
But I don't know anyone personally who dwells perpetually without unconscious thought. That may be enlightenment; I'll tell you if I find out.
