Where is the switch?

I hate having so little control over what my brain will focus.  It's tiring, maddening, and frustrating.  Sometimes, it works.  If I am lucky, I'll have a bounded project with a definitive deadline and a clear sense of what needs to be done to get it all done.  If I am luckier still, circumstances will allow me to focus on it non-stop and without interruption.  At some point, the stars will align, and I'll be able to work on it to completion.  More often than not, interruptions are the rule rather than the exception, multiple projects and activities are the order of the day, and determining how to proceed is a project in and of itself.  Even when all is clear, the interruptions can stop progress in its tracks.  I live in fear and anxiety of such events when truly pressed by a deadline.  Down deep in my gut, I know that if I am forced to stop, give way to another task, my attention may be forever diverted never to be regained until some magic switch is reengaged.  I've yet to figure out how to make it come to heel.

When I was able to take Ritalin, things were better.  Not great, but better.  I didn't quite have the ability to choose where to put my attention the way I want, but I was better able to put aside the self-distractions and regain my attention if diverted by outside stimuli.  It reduced the stress and anxiety, making me calmer and, according to my husband, much more pleasant to come home to.  I take Adderall now, but it doesn't work nearly as well ... or really all that well at all.  At times, it makes me want to cry when I can't get done those things that I want.

Where is the switch?  How do I turn it on?