If I were to be truthful, I would have to tell you that I did not focus on finding joy yesterday. How sad! I woke up this morning, realizing that I did nothing but buzz around all day yesterday, forgetting to seek new sources of joy. Admittedly, I was also feeling sorry for myself because I had an eye appointment and my eyes were dilated,which is always unpleasant. I bemoaned the fact that I still had hours of preparation work to do for my teaching day today and due to my lack of planning I was faced with literally no vision to do it. The worries of today crept in and stole my joy of yesterday. And now, that day is gone, never to be given a second chance. As I face one of the most important days of my week, I realize I am completely unprotected against joy-stealers. Thank God, I have His word any time I need it. His promises are made new every day! Thank you, Lord, for the reminder that you are my ultimate source of joy. Never ending, never ceasing.
…For this day is holy to our Lord. And be not grieved and depressed, for the joy of the Lord is your strength and stronghold.Nehemiah 8:10
“I’ve told you these things for a purpose: that my joy might be your joy, and your joy wholly mature. John 15:11
bonafidelife 
I trust your school day had many joy-gems in it. I love the times when I am small but God is large in my classroom!