Instead of focusing on being 'present' and doing things in a mindful manner, cut yourself some slack by doing something that's enjoyable and a 'mindless' activity. It's like giving your brain a breather. Try doodling: it's effortless and an extremely satisfying activity.
So what, now what? Keep a tray of art supplies on your table or desk. It could be crayons, pastels, ink, clay or (scent-infused) playdough.