Change and Love are certain
Look at your life. Examine it closely. What makes you happy? What makes you sad? What do you desire? What do you avoid?
If you do not watch your life carefully to see how you are using each precious moment, then you are living in a state of hypnosis. To eliminate such swings in your emotions just accept that most of your suffering is self-induced because you are not accepting that change is inevitable. Change and love are the only two certainties in life.
What are the causes of your states of happiness or unhappiness? Most suffering comes from craving for life to be other than it is. Accept that life is as it is and all things are impermanent. Embrace each experience as it occurs and be ready for the next.
How can we prevent suffering? By dropping limited ideas and perceptions about ourselves and others around us. Experiences can be unlearned, can be detached from. We can live life as the pure energy that we are.
To be completely enduring happy we must abandon expectations about the way we live. This is the correct perspective on our short human lives, and to get this perspective, just close your eyes and breathe. Meditation and attention to your breath will make you aware, and awareness is the key to enlightenment.