With the past, I have nothing to do; nor with the future. I live now.

Yes, I know you have to plan for the future, but you don’t know what path it will take. Plan for multiple scenarios if you want.

I heard this saying in different words: Yesterday is history, tomorrow is a mystery, I live for today (Kimi Raikonnen).

Life goes by fast.  Stop suffering for things you did in the past.  There is nothing you can do to change what happened.

Stop worrying yourself about what might or might not happen tomorrow.  Tomorrow will take care of itself.  You have the past as a guide to know how to deal with it.