You may, not making a diagnosis, but you may have something further going on then simple depression
, there are about 8 different types of depression
, as well as mood disorders which have depression as a symptom. It's nothing you have done, nor should you blame yourself in any way (I wish I could give you a hug) it's your brain. The brain is such a complex organ, far more complex then even the biggest computer out there, and science has only tapped the surface.