Missed opportunities can often create a sense of despair. So, what do you do?
Oswald Chambers gives insight:
"Whenever we realize that we have not done that which we had a magnificent opportunity of doing, then we are apt to sink in despair, and Jesus Christ comes and says—‘Sleep on now, that opportunity is lost for ever, you cannot alter it, but arise and go to the next thing.’ Let the past sleep, but let it sleep on the bosom of Christ, and go out into the irresistible future with Him."  Chambers, Oswald. My Utmost for His Highest: Selections for the Year. Grand Rapids, MI: Oswald Chambers Publications; Marshall Pickering, 1986. Print.
So, don't let despair paralyze you! Arise, get moving with the Lord.