We cannot undo a single act we performed. Nor can we erase a single word we've said. Tomorrow is beyond our control. Tomorrow's sun will rise either in splendor or behind a bank of clouds - but it will rise. And until it does, we have no stake in tomorrow, for it is yet unborn.
Any person can fight the battles of just one day.
It is only when we add the burdens of yesterday and tomorrow that we break down. It is not the experience of today that drives people mad - it is the remorse for something that happened yesterday, and the dread of what tomorrow may bring.