Come back, sweet yesterdays!
Sweet yesterdays, come back!
Ah! not in my dreams only
Vex me with joy, to wake
From dream to truth, twice lonely,
And with renewed heart--ache.
Let night be wholly black,
So day have some kind rays.
Come back, sweet yesterdays!
Sweet yesterdays, come back!

Robert Laurence Binyon

http://www.poemhunter.com/poem/come-back-sweet-yesterdays/