There is a great difference between worry and concern. A worried person sees a problem and a concerned person solves a problem. So, be a concerned person.
Do not only be close with someone who makes you happy. Be close with someone who cannot be happy without you. It makes a lot difference to him at least.
It is better to conquer yourself than to win a thousand battles. Then the victory is yours. It cannot be taken from you, not by angels or by demons, heaven or hell.