It is said that we remember God more deeply in sorrow, than in happiness. How can we keep ourselves even minded even in happiness, so that we can still be unruffled and detached, centered on God. Because I have always felt that for me happiness is followed by equal pain. How do we negate the two and stay God centered even when we seemingly feel we have 'everything'?
You have asked an important question.
Pain and pleasures are a part of the dual nature of delusion. In daily life we experience pleasure and pain as a part of desires, likes and dislikes.
When we meditate and withdraw from the five senses, we connect with the soul, and begin to experience soul happiness. True happiness has not opposition, as it is not a part of duality, and it is not conditioned by outward circumstances.
Daily practice of meditation will help you to withdraw from the five senses and connect with the soul, where you can experience one of the divine attributes of God such as peace, joy and love. During the day, stay connected with God, by practicing mini meditation, repeating japa, mantra, or chanting.
Try to do everything with God, and remember that He is always with you. Share everything with Him. The daily practice of God’s presence, will keep you connected with the true source of happiness, being untouched by the fluctuations of good and bad, and help you remain even minded and cheerful no matter what.
It takes discipline and self control to remember God and not forgett Him, but the more you practice, the happier you will feel.