I can hyperfocus. Fortunately that worked for me when revising for exams. Music on, coloured pens out, room covered in post-its, tape recordings of me talking to myself in French. I also got "in the zone" for my disertation, although should have engaged with my tutor more.
The revision advice of "take regular breaks" is anathema to me. I find transitions hard, so once I'm into something, I have to roll with it until my steam runs out. Stopping after 45 minutes would kill half the day by the time I focus on getting back to it.
This year has been awful for my function as I need external stimulation to focus and otherwise end up drowning in an abyss of time and possible options.
Even things I want to do get procrastinated and avoided.DH working from home is nit compatible with my need for the radio to be on in stereo around the house, and to liberally sing as needed 
Teaching was a good career between the structure of the school day, some creative freedom and no two days being identical, and I had to be present in the situation. I am the world's least productive SAHM! (DS needs quiet time at home and doesn't cope with wrap around care)
My attention span varies wildly through the day. My best time is 6am then picks up through the evening.
I get very frustrated with myself because I know what its like to feel productive, but I find it very difficult to create and fake that mood and much of the time it's a battle to do simple, basic life crap.
Sonique is currently singing in my head. Goodness knows where she came from!