The Twilight Zone - Season 1 Episode 27 : One Life, Furnished in Early Poverty 1989

Angry with his adult life, a man, Gus Rosenthal, returns to his childhood stomping ground in Ohio and while digging up an old toy soldier finds himself transported back to when he was a boy. Taking on the guise of a writer he meets himself as a child - angry, frustrated and misunderstood. Taking the name of 'Harry Rosenthal', Gus tries to guide his younger self but sickens from his place out-of-time. When he has to leave he tells his younger self to stay behind...which was what frustrated himself as a child and led to him being so angry throughout his life. Returning to his own time, the old Gus returns to his life, sadder but wiser.