This may sound stupid, but I survived my bout with PPD without meds, herbs, creams, etc. I was determined to do mind over matter (which I realize isn't possible for everyone) because my body does NOT respond well to messing with chemical/hormonal levels by taking medicine.
I talked about the thoughts going through head, I wrote and wrote and wrote (often just the same two or three words line after line since that was the only coherent words my brain could muster), I surrounded myself with inspirational quotes, I kissed my kids cheeks as much as I could, I made countless lists of all the things I was grateful for, I tried (but didn't always succeed) to eat healthier, and I tried to train as much of my focus as I could AWAY from myself.
It was slow, but constant improvement. I feel so much better than I ever did trying to solve things with medicine.
I really hope you find something that works for you too! If your body doesn't like outside interference either, you might try what worked for me. Sending good luck and happy thoughts your way!!