I believe that PPD can trigger ongoing depression if it is not treated. Well at least that is my take on my personal situation. Unfortunately, I was on medication and went to therapy intermittently. It just hasn't been enough yet for a break through and my kids are 4 and almost 2. I was also redisposed prior to and other situations not related to pregnancy and children also have impacted me. I would encourage you to look at all aspects of your life and see if there is something that is not related that could be causing to distress.