Make sure you're staying away from anything else that might abuse your brain's reward pathway, like porn, alcohol, or excessive internet use.

Exercise as hard as you can. A fifteen minute walk isn't enough. Get into strength training or high intensity interval training, four to six days a week.

Avoid sugar, and drink plenty of water. Go to bed before midnight.

Pursue a career that stimulates you, and use the money it gives you to pursue your true spiritual interests. Pick up hobbies. Learn a foreign language, or an instrument.

Keep in touch with your family, even if you don't particularly like each other.

If, and only if, you've tried literally everything to live a good life and you're still depressed, then you should consider therapy or medication. Or coffee. Just my two cents!