The routine you imagine on a quiet Sunday may meet a very different calendar by Wednesday. Make room for both versions of your week.
Start with the calendar you have
Before adding a new commitment, look at the ones already there. Work, travel, family, and personal time all deserve an honest place in the plan. Choose a small number of commitments you are prepared to protect.
Decide what happens when plans change
A disrupted week does not need to become an undefined week. Decide in advance how you will review your plan when something moves. You might reschedule an appointment, simplify a project, or ask for help choosing an alternative.
If your commitment involves physical training, choose changes with someone qualified to understand your circumstances rather than treating a planning article as an exercise prescription.
Keep a simple record
Use a note or calendar to record what you planned, what happened, and what got in the way. A short sentence is enough. The record is there to help you make a decision at your next review.
Review without making it a verdict
At the end of the week, ask: What was realistic? What did I underestimate? What should I adjust? Treat the answers as information for the next plan, rather than a judgment about who you are.