What we need to figure out here, is not so much "Why are we so sad?" but more, "How can we attain joy again?"
Possibly we have lost sight of what it means to have joy. We have forgotten that happiness is temporary and unfulfilling. We have forgotten that true joy comes only from God. We have chosen, most likely indirectly, to pursue happiness instead of God, instead of JOY.
We must shed the mindset of one who is a victim of fate or trapped in despair, and put on the armor of God. We must force ourselves (at first it will be by force, then by habit) to count our blessings, not our losses. To never be content with what we have here in this world, and yet to never desire more of what the world can give. We must eagerly desire the greater gifts, and pray continuously for such gifts. We must take captive every thought and make it obedient to Christ. We must test every thought before it fully forms (before it enters our minds, or especially our hearts) and if it is a complaint, turn it into a healthy desire for improvement. If it is an expression of hopelessness, turn it into an acknowledgement of the ultimate hope we have in Christ. If it is a doubt, turn it into a question you will ask. If it is a fear, throw it away and instead choose a reminder of God's love for you. If it is a selfish thought expressing only hatred for an unchangeable circumstance, throw it away. Just leave it behind you. Who of us by worrying can add a single hour to our lives? And if the world hates you, remember that it hated your Savior first. Do not expect this world to be your home, and do not dwell on the fallen nature of things. Set your mind on things above. Whatever is right, true, lovely, pure, noble, excellent, praiseworthy... think about such things.
Immerse yourself with joyous thoughts, let each task the Lord sets before you be a chance to offer your gifts back to him. Make a decision to find joy in your life, but first decide that sadness is not worth it. Decide that you're not being fake by throwing away your sorrows, you're simply trusting God. You're not suppressing your feelings by choosing to constantly bear the fruit of joy, you're just refusing to mourn forever. You're just refusing to remain in self-centered sorrow for longer than it takes to realize that you either will or can't do anything about it. Choose to let God lead you out of the darkness and into the light. Your sorrows only last for the night, so why are you covering your eyes? The sun is rising in your heart, whether or not the world has actually improved. Don't waste time with complaints and regret. Your attitude should be like that of Jesus Christ. Yes, there is a time for weeping, but nothing should ever steal your joy.
Jesus loves you more than you know! Don't worry about anything, pray about everything! Jesus and I are here for you, be happy! :D
