“Struggle in life brings worries and the worries are the sources of unhappiness. So take it easy.”
Related quotes

The "Tetrapharmakos" [τετραφάρμακος], or "The four-part cure" of Epicurus, from the "Herculaneum Papyrus", 1005, 4.9–14 of Philodemus, as translated in The Epicurus Reader: Selected Writings and Testimonia (1994) edited by D. S. Hutchinson, p. vi

“A life spent defensively, worried, is a life wasted.”
Source: Every Second Counts (2003), p. 21
Context: A life spent defensively, worried, is a life wasted.
You know when I need to die? When I'm done living. When I can't walk, can't eat, can't see, when I'm a crotchety old bastard, mad at the world. Then I can die.

Source: The Causation and Treatment of Psychopathic Diseases (1916), p. 33

“"It works, why worry?" is life's deepest philosophy.”
Out of Control: The New Biology of Machines, Social Systems and the Economic World (1995)
Source: The Wheel of Time: Shamans of Ancient Mexico, Their Thoughts About Life, Death and the Universe], (1998), Quotations from "Journey to Ixtlan" (Chapter 8)

“Don’t worry, there will always be something to worry about.”
Humor in Psychotherapy (2007)
“By worrying a lot, we become a nation of worries.”
Calbayog bishop shares 3 elements of a ‘peaceful life’ https://cbcpnews.net/cbcpnews/calbayog-bishop-shares-3-elements-of-a-peaceful-life/ (May 23, 2018)