I've been working over 70 hours a week since late May.
There is no feel for Mondays vs. Fridays. The only days I occasionally have off is Sunday and most of the time, that involves just catching up on other shit that I put off throughout the week. I suppose Saturdays are the most casual since those are almost designed to be "catch up on workload days."
I don't really mind that much since I get compensated for all my time. I'll be clearing well over $100,000 this year. It's worth it for now but this clearly isn't sustainable in the long term.