Will natural progesterone help with pregnancy depression?

To start from the beginning I had never had any type of depression until after I had my first baby 2 and a half years ago. Right away I got really bad post partum depression. I tried anti-depressants and hated the side-effects. I saw natural doctors who tried diets and homeopathic remedies and vitamins. Finally I found ‘The Hotze Health and Wellness Center’ online after a year. They really helped alot. They assesed my thyroid, and hormone levels, especially progesterone (which I was taking days 15-28 of my cycle) since your progesterone drops greatly after giving birth and can sometimes have a hard time picking back up which causes the depression. Anyway–I am pregnant for the second time and I’m feeling a depressed again! I called them right away and they said for the first trimester I should continue my progesterone everyday. I started that up again and it’s helped a little but not alot and I’m scared to feel like this through out my whole pregnancy, I’m ready to be excited about this pregnancy even though it wasn’t planned. So my real question is " Will these feelings go away" and "I thought during pregnancy progesterone was made in LARGE quantities so why should I have to take this natural progesterone?"