Monkey mind, as it is called by some, has its value. In those with ADHD,monkey mind also comes with a partner–obsession perfection-addiction, but another mind set with decided value. Balancing on the sword edge of these two states takes nimbleness and nimbleness can be learned.
Two Staying Strong Tips that have served me well: Observing a Shabbat–a day away from all work, all electronically connected busyness, and all spending money. The second is a smaller but very useful tip. Setting a timer for half hour or hour intervals. Can’t leave a task until the timer rings; must take a quick break when it does.
Good luck on that biggest job. Hope it is designed to bring peace on earth. Stay strong.