Sadness is a symptom. Mind/Body is saying something is wrong and it needs to be changed. Medication just dulls the pain. It is not a solution. The real solution is changing the way of life so that it becomes more fulfilling.

Happiness is not a easy thing to achieve. You need to fix the body, eat right, exercise, control/watch your thoughts, let go of things beyond control, enjoy what is in front of you instead of chasing some imaginary future.