I searched on Google and YouTube, but I didn't find any results about "over the grind" at all. And I'm not sure what it means. However, I found "grind (down)" which is perhaps a synonym (but again, I'm not sure and would like clarification.) Finally, the example I saw from an Australian newspaper
if you're over the grind of your 9 to 5 job and longing for an adventure, this story might just be for you!