You have it easily in your power to increase the sum total of this world's happiness now. How? By giving a few words of sincere appreciation to someone who is lonely or discouraged. Perhaps you will forget tomorrow the kind words you say today, but the recipient may cherish them over a lifetime.
Do you remember the things you were worrying about a year ago? How did they work out? Didn't you waste a lot of fruitless energy on account of most of them? Didn't most of them turn out all right after all?