If you find yourself venturing into the past or future through thinking, it is almost always because an uncomfortable feeling lies beneath the thinking, and thought provides a means of escape. Escaping boredom, expectation, longing or seeking through thought does nothing to diminish the feeling itself. It merely avoids it. When you return from your excursion into thinking, the feeling will still be there.
The peace you long for is not found by escaping uncomfortable feelings through thought. It lies in the opposite direction. It lives in your being, just beneath your feelings.
If you find yourself lost in thought, trace the thought back to the uncomfortable feeling that underlies it, the feeling from which you are trying to escape. Then sink deeply into that feeling. Sink into the boredom itself and, at some point, you will pass through it and discover the peace at its depths.
If your thoughts are like ripples and waves on the surface of the ocean, your feelings are like currents and eddies in its middle layers, and the peace of your being is like the silent depths. So if you find yourself resting on the surface, surfing the waves of thought, sink down into the feelings that underlie them, and then sink further into the quiet depths of your being.
Be sensitive to the slightest feeling of longing, even if it has no particular object. It may simply be an existential sense that something or someone is missing. What you long for lives just beneath that feeling. Longing itself is never fulfilled; it only subsides.
Each time a desire is fulfilled through the acquisition of an object, substance, activity or relationship, the impulse of seeking does indeed come to an end. As this impulse subsides, you taste the peace that is the nature of being. But the mind soon rises again and attributes this peace to the object or experience that preceded it, initiating yet another cycle of seeking.