Heather, I can relate. If you can even imagine this, I sometimes start obsessing on XAH, and my practical mind kicks in and says "think of something else!" And I get mad at myself for thinking that, because I'm so used to obsessing it has become my comfort zone! My therapist says that I'm still trying to parent him, and since I did it for over twenty years, I won't be able to break the habit without alot of time, work, and practice. But at least I'm finally getting that little voice to kick in and tell me to let it go. Usually I do, but ... old habits die hard.
No advice, just a hug. Keep plugging, you'll get there.