After 4 days of sitting (<4,000 steps/day), you become "exercise resistant" and don't get some of the usual acute metabolic benefits (blood sugar, insulin, triglycerides) from a 60min workout. Potential interaction between sitting time & exercise habits:
The key to success in sport is consistency. Nothing else is as important. Doing the wrong stuff consistently is better than doing the right stuff inconsistently. Take training one day at a time following a flexible plan. If you miss a workout just get back on plan the next day.