How Do You Manage ADHD and Distractions?

I have been given a very gracious deadline extension for the work I have to turn in in order to pass. However, given the currently overwhelming family circumstances and this stupid ADHD I have, it's so hard to concentrate. I end up writing a sentence or two, then walking around and curling up with the big doggo for a while, go back to the desk, rinse and repeat. How do I make myself focus?