I found this quote on the blog "Build this House." I used to list in on my sidebar, but thing were getting a little long over there, so decided to publish it as a post.
I believe there are: "Two Days We Should Not Worry" By Author Unknown
"There are two days in every week, about which we should not worry, two days which should be kept free from fear and apprehension. One of these days is Yesterday with all its mistakes and cares, …we cannot erase a single word we said. Yesterday is gone forever. The other day we should not worry about is Tomorrow with all its possible adversities, its burdens, its large promise and its poor performance; …Tomorrow's sun will rise,either in splendor or behind a mask of clouds, but it will rise. Until it does, we have no stake in Tomorrow,…This leaves only one day, Today. Any person can fight the battle of just one day. It is when you and I add the burdens of those two awful eternities Yesterday and Tomorrow that we break down. It is not the experience of Today that drives a person mad,it is the remorse or bitterness of something which happened Yesterday and the dread of what Tomorrow may bring. Let us, therefore, Live but one day at a time."