If you're having a rough time in life, you probably don't appreciate people spouting cliches like "chin up." Next time you're tempted to minimize someone else's problems, don't. Respond with empathy in the same way you'd want others to do for you.
Is there something on your mind? As much as you'd like to keep it a secret from friends and family, they probably know you're holding back. The topic needs to be brought out into the open to ease the burden on you.