You've earned today's rest, but that doesn't mean you get to go crazy with cheat meals and undo all of your progress. If you find yourself absolutely wiped from the past week, take a hard look at your food intake. Are you sticking to the proper ratio of carbs, protein, and healthy fats? With the addition of interval training to the weekly regimen, it's now more crucial than ever to properly fuel yourself with adequate carbs, especially around your workout.
If you're feeling particularly sore or tight, take some time to stretch throughout the day and foam roll. Don't have a foam roller yet? It's a worthy investment! Even tennis, lacrosse, or softballs will help you massage tight spots and work through particularly sore areas on your body.