I hear you. I missed Palm Sunday Mass (wife in the ER all night) and really feel my week is off-kilter.
I missed the most important meal of my week and have a very empty feeling.
I have never heard of Divine Mercy Sunday. But then I have not been a Catholic very long. We always called the Sunday after Easter “Low Sunday.” I forget why. In the Episcopal church it included the Blessing of the Tartans, which was exciting if quite noisy.
“The Catholic Church teaches that it is a mortal sin to miss Mass on Sundays without a good reason.”
What would constitute a “good reason”? Other than being in the hospital, for example, or in a very small town in Rural Alabama where Baptist and Methodist were your only choices?