There comes a time in everybody's life where depression kicks in. But, do not worry. There is a way out from this. I recommend you do Sirsasana at least for 15 minutes every day (Caution: Savasana must be done after Sirsana). After sirsasana and savasana, sit in a comfortable blanket or mat either in sukhasana, siddhasana or padmasana. Then after resting for some time, do some Pranayama. Just do 3 simple pranayamas. These 3 are simple and yet very powerful. 1) Do Bhastrika 2) Do Kapalbhati 3) Do Anulom Vilom. Then take some rest. After this, do So Hum meditation. Close your eyes, place your palms facing up making gyan mudra in your knees. Spine erect, bring your awareness to your breath. Feel the inhalation and feel the exhalation. During inhalation chant "So" mentally and during exhalation chant "Hum" mentally. Meditate at-least for 30 min. everyday. After you do all this for a month, you will experience a drastic change in you. Also, start drinking lemon tea every morning till your depression goes away. Do all this with moderate diet and green leafy vegetables, you should be fine within a month.
Om Shanti.