What Are The Symptoms Of Depression?

I have not been able to get enthusiasm about my work past a couple of months. I feel empty and meaningless. Don t feel like waking up in the mornings, not that I love sleeping. There is a sudden sinking of heart at times (almost daily) I feel guilty, sad and often burst into tears. I often I punish myself (slapping myself/punching wall etc) for not meeting my work target or wasting time. Overall I feel meaningless and I have a strong and constant wish that my life comes to an end ASAP, however, I am not suicidal, the thought of suicide scares me. Does this relate to depression or its just normal and bad phase of life?