In other words, I go from overwhelmed to under-whelmed, in a cycle, and I don't know how to break it. I set priorities, but one of the aforementioned 'insignificant details' catches my attention, and before I know it, the cycle has started again. It's frustrating.
If so you need to grieve for the pain you suffered in childhood. As well as grieving and letting go of your pain and the distressing memories present in your subconscious (which you may no longer be aware of), you need to choose one of your three goals and focus on that alone.
Practice giving less energy to visualization techniques around that goal and less energy to the irrelevant details and use the energy released to focus more on practical steps you can take to move toward your goal. If a step appears to large or difficult, break the task down into a series of smaller steps and then focus all your energy on achieving the first one (no matter how small) and then reward yourself for your achievement. If doing this brings up stress and pain you need to release it as it arises. This process will act as a cleansing and retraining that will gradually bring you back to center.
As you work with this process there will come a time when the level of psychological pain will subside. At this point I suggest you take up meditation. A regular daily meditation practice at that point will accelerate your return to center and improve your powers of step by step focus.
By releasing your pain, reducing old habit patterns and focusing this spare energy on the simplest of simple steps, you will gradually and inexorably move toward your first goal. When you have achieved that goal the other two will follow. At that point you will have successfully reprogrammed yourself to return to center. Your frustration will have gone and you will feel a depth of peace and contentment greater than you have ever known.
Further Help and Resources
If you wish to explore releasing your psychological pain and learning to practice meditation I recommend the guidelines given in my book Unfold Your Wings and Watch Life Take.
Bill Cozzolino has a great free manual on meditation: The Nuts & Bolts of Meditation.