I also tend to overanalyze things, but books like "Atomic Habits" and "The Slight Edge" were really helpful. It made realize that there's no point to try to properly define what a task is, as what I can do at any given day depends on my physical and mental state.

How I perform when I have a bad day is completely different from my performance on a good day. Something that's a task today might not be considered like one tomorrow.

There'll be days where I'll only do 25 small things then call it a day, and that's okay.