Distracted

I am a very focused person. I set my mind to a task and will complete it without straying. Usually.
Lately, I am a mess of all things unorganized. Don't get my wrong, in this past week, I have scrubbed my house from top to bottom, but it has not been without struggle to stay on task. I'm not sure what it is, whether I'm suffering from adult-ADD, but my mind and thought are ALL OVER THE PLACE.
Right now, as I am supposed to be compiling my meal plan and grocery list for the next two weeks, I cannot for the life of me, actually sit down and complete it without being drawn to all things non-grocery. It's beginning to make me insane. I don't know whether I'm subconsciously avoiding something (perhaps something terribly haunting at the Commissary?) or if I just am not making enough effort to control my attention. I've even had issues engaging in conversation lately, not being able to listen thoroughly or even straying from my own thoughts when I'm speaking.
Who knows. I guess I'm just going through a "...look there's a squirrel"-phase. Eeek. It better end soon.
Any tips for better focus or concentration?