Just make sure you have not added and activated any trains on days you do not want to use the pass.

You can always deactivate up to 11.59pm on the day before. Once a day has begun, (as in past midnight)  any active travel listed for that day will take and use up that day.

Make sure you have not activated any other travel days yet. If today is your first day, then after activating your pass and the first travel day, there should be 5 travel days left. You can see that under "My Pass”, where it should say: "Travel days 1/6 used”. If you used more, then select the other travel days one by one and cancel them. Never activate anything in advance. A few minutes before boarding is good enough.