The word 'psychology' comes from two Greek words; psyche and logos.  Psyche was the goddess of the soul and logos can be translated to 'meaning'.  Psychology, then,is about the search for a meaningul life for our our soul.  When we lose touch with our sense of meaning and purpose, it causes us distress, which can come in many forms:  depression, anxiety, addiction, feelings of emptiness, or just a futile search for happiness that seems always to be just out of reach.
While medications can sometimes lighten our suffering, what psychotherapy can do that medicine cannot is to help us to feel in control of our life again, help us to let go of old patterns, old fears and old ways of avoiding life, so that we can feel the energy and excitement of life again. 
Life is not meant to be endured or gotten through, it is meant to be lived, fully alive.  While no one can feel on top of the world all the time, if you haven't been feeling energized by your life, don't let the days weeks or years go by thinking that's all there is.  Give yourself a chance to live it more fully.