"At times, so many memories trample my heart that it becomes impossible to know just what I'm feeling and why: my first love laughing in a park whose name i can never recall; my grandmother dying near her dirty Brooklyn bricks; the dizziness of the Rockies telling me to go back among the living; my ex-wife's shoulders slouching tired in the rain; the old dog I used to live with chasing her tail... and a thousand more...."
What memories "trample your heart"? I'll add some of mine in the comments and I encourage you to do the same.
Is it wrong to think about past tragedies? No. Life is meant to contain both joy and pain, and the blessed struggle of life is the struggle to maintain balance. Einstein said the way to keep your balance on a bicycle is to keep moving forward.
In the June 2 entry, Nepo goes on to say,
"Tragedy stays alive by feeling what's been done to us,
while peace comes alive by living with the result."
Adapt, overcome, keep moving forward...