You know what some of the hardest water I've had to deal with in life is?
Water under the bridge.
The Lord taught us to keep our minds on the present:
"Therefore do not be anxious about tomorrow, for tomorrow will be anxious for itself. Sufficient for the day is its own trouble."
(Mat 6.34 ESV)
"Sufficient unto the day is the evil thereof - Αρκετον τη ημερα η κακια αυτης, Sufficient for each day is its own calamity. Each day has its peculiar trials: we should meet them with confidence in God. As we should live but a day at a time, so we should take care to suffer no more evils in one day than are necessarily attached to it. He who neglects the present for the future is acting opposite to the order of God, his own interest, and to every dictate of sound wisdom. Let us live for eternity, and we shall secure all that is valuable in time." (Clarke, Commentary)
I must confess that not only can I be anxious for the future but I can be haunted by the past. Feeling the pain of wrong choices is trying enough; however, living with the consequences of inaction may be worst hurt of all.
Lord, have mercy. Christ, have mercy. Lord, have mercy.