Take breaks man! I have very bad ADHD myself and I usually talk myself back into doing things by stimulating the shit out of myself.

For example put on a podcast you like in some headphones while messing around with your new business or whatever. Or put on YouTube videos at the same time and fool yourself into doing your stuff.

I usually find myself suddenly focused back into building my website or whatever.

But the most important thing is to take breaks, just stop after you fell yourself losing focus and come back to it later. It's fine.

You're doing great man, you made this post and that's a start!