You need a doctor's for the exact figures. Just saying "a pill" without dose is btw completely irrelevant.
And yes, you'll pee most of it out what you can't absorb.
Something to check for is vitamin K (not sure about your local naming scheme though y shot seems to suffer internationally). You're body needs that stuff to absorb the B. I actually have a K production problem, that's why I was B deficient.
Doctor prescribed 10k I.E. B with fitting K - daily! That's a crazy amount that would be absolutely useless without my specific circumstances.
And one more thing: ADHD or not you need to find your way to remember medicine. D just kills your mood, blood pressure in a few years might just kill you.
My approach for example is a the tier alarm system, mix of voice assistant, a daily mail and push notifications. Plus I have my medicine both at home and at work.
I assume we're in a similar boat so let me assure you: no, you won't - because we wouldn't even realize it happened.
Only after s few months one of us will recall this thread and be like "oh, yeah. Twitter. Seems really dead finally. Good."
And to be clear I expect they person to be you because my memory is awful.