If a believer cannot commit the unpardonable sin, then I have nothing to worry about.
The only way someone can commit that sin is as an unbeliever and at that point there was no forgiveness to lose in the first place because they never had it in the first place.
All your future sins are already forgiven, unless you commit the unpardonable one, in which case you dont have the Holy Spirit living in you and therefore you lose the forgiveness for all your past, present and future sins that you once thought you had.I.e., you were wrong.