Wonderful to know that impulsiveness is your main derailer because it’s not so hard to work around.
I experience the same thing only externally when I’m focused on one thing and then get a notice that I need take care of this different thing asap. They can both be handled in a similar way with an if/then statement.
So, this morning, you might have said, IF I get an impulse to do something else before I finish this task, THEN I will evaluate whether it MUST be done right now or whether it can wait till I finish. IF it must be done now, THEN I will do [THIS] to help myself get back on track when I return. IF it can wait, THEN I will do [THAT] to remind myself to do it next.
Impulsiveness isn’t always a bad thing and it can be fun and engaging in the right circumstances, such as when on vacation. It’s only a problem if it interferes with something we need or want to get done. What helps me the most is to put myself in different modes, for example, deep focus mode, efficient, work-fast mode, or relaxed mode.
When I put myself in a particular mode, acting the way I need to becomes more automatic. One characteristic of ADD is that although most of the time those folks are distracted, they can also fall into a hyper-focused mode when they’re engrossed in something. This is similar, only it’s a mode you consciously activate rather than fall into.