Yesterday you can't alter, but your reaction to yesterday you can. The past you cannot change, but your response to your past you can.
Here's what you need to keep in mind. You no longer have yesterday. You do not yet have tomorrow. You have only today. This is the day the Lord has made. Live in it.
What if you woke up this morning and had only the things you thanked God for yesterday?
Write today's worries in sand. Chisel yesterday's victories in stone.