Depression can appear in different ways in different people. Generally it is characterized by a loss of interest in the things that used to bring you pleasure, and feeling sad or "low" every day for at least 2 weeks. Other symptoms of depression include: self-isolation, irritability, significant weight loss or weight gain, insomnia or sleeping too much, and difficulty concentrating. If you think you may be depressed, therapy is recommended.
One way of treating depression is through CBT, or Cognitive Behavioral Therapy. Briefly explained, CBT works this way: our thoughts determine our feelings. When we are depressed, our thoughts (or cognitions) are "distorted," meaning they are not truly accurate, although we may believe they are. A depressed person thinks thoughts that are self-discouraging and self-critical. It's often said that depression is "anger turned inward." When we use CBT, we identify the false cognitions and correct them.
Other modalities that are used successfully for depression are Mindfulness and Talk Therapy. I often give small homework assignments if you would like to have something to work on during the week.
Having the opportunity to talk through the issues that have been weighing you down in a supportive, non-judgmental environment with your therapist can be a great relief, and lift the burden you have been carrying.
Making the first call or sending that first email just might be the hardest part. Take that step, and let the rest follow.