Share your problems with someone you deeply trust, and tell them how you want to make yourself better. Believe me, if that person loves you and cares for you, they'll try their best to promote you to quit smoking and improve your diet and make you happy. It's very difficult if you try to change yourself on your own because you're already the sufferer, and a sufferer can rarely be the healer. Trust me, go and find a healer for you. If you don't feel you have anyone that close, no one is a better healer than a psychiatrist, the real healer.