"If thou art sorrowful, call on the Lord thy God with supplication, that your souls may be joyful." Doctrine and Covenants 136:29 To feel happy is the ultimate quest of most people. The Lord has given us instructions how to obtain.
"And now, verily I say unto you, and what I say unto one I say unto all, be of good cheer, little children; for I am in your midst, and I have not forsaken you;" Doctrine and Covenants 61:36 Happiness and cheer are a choice. Even in the darkest of hours, there is always evidence that we are not alone or forsaken.
"Cast thy burden upon the Lord, and he shall sustain thee: he shall never suffer the righteous to be moved." Psalm 55:22 Jesus will help on those down or troubled days, because He wants us to succeed and return to live with Him and the Father again.
"Come unto me, all ye that labour and are heavy laden, and I will give you rest." Matthew 11:28 Physical, emotional, and spiritual fatigue get us down in different ways. Jesus will help with all of these. He will lighten our burdens and our spirits if we choose to allow it and ask.
"And now, my brethren, I desire that ye shall plant this word in your hearts, and as it beginneth to swell even so nourish it by your faith. And behold, it will become a tree, springing up in you unto everlasting life. And then may God grant unto you that your burdens may be light, through the joy of his Son. And even all this can ye do if ye will." Alma 33:23 Studying and feasting upon His Word, we grow closer to Jesus and the Father. When we understand the reason for earthly experience, it is not so hard. When we feel them near, it is comforting and therefor easier to endure difficulties gratefully, gracefully, and graciously.
"Therefore, cheer up your hearts, and remember that ye are free to act for yourselves—to choose the way of everlasting death or the way of eternal life." 2 Nephi 10:23 Finally, we are free agents and don't have to get down during hard times. I know I'm not alone. Because He lifts me up, I choose life.