The big slow down
I'm a sports fan. Around the game, one often hears reference to the 'speed of the game' and how it changes from one level to another - from high school to college and from college to the pros. A common line is: "The game is starting to slow down for him, so he is playing better/making adjustments - winning more." If you are a parent and have taught a child to drive you understand this idea as well. Very likely you've driven for a long time, so you know how to anticipate and where to look for danger. Young drivers don't have that experience and so everything is happening fast for them; experience has not yet taught them all the lessons you have learned.
How fast is your work life? Is is running the speed you want it to run? Mondays can be tough days for me if I let them. Often the size of my to do list and/or competing priorities can wind me up. If I don't focus, I look at all that stuff, and think it needs to be done right now. Add in new interactions from email, and other sources - and the speed can be too much.
Find tactics that work for you to slow things down. For some it is exercise. For others maybe it is only reading email two times per day. For still others it is making lists and prioritizing them. Sometimes a change in scenery can be what is needed - work from a new place in your office, if you can't go off site. Experiment with ways to slow down your work life. It is the best way to offer your best work.