What Causes Depression And Anxiety?

Hi, I am writing in regards to a question I have for depression/anxiety. I have been on different types of anti-depressants after I had a major depressive episode about 12 years ago. I have since relapsed due to the fall out of a relationship. I ve been trying a new anti-depressant. I get the same mood trends at same times of the day like clockwork. I wake up with depression and around 11:30 everything switches to anxiety and around 2:30 is when it s the worst. I have self-medicated with the depression over the past 12 years on a regular basis as well. I m trying to figure out what is what.