Quoting Tiffany Gillette:" I just don't like the thought of something altering my brain and my thoughts and who I am. I feel like ... [snip!] ... away from who I am... & no one understands that, so I must just be really freaking crazy for feeling this way apparently."
If you don't want to take a pill, I'd set up counseling first and see if that helps. I don't like taking medicine either, because like you, I just don't like the idea of being "altered". I had horrid PPD after my second was born. I truly believe I was borderline PPP. I went to counseling and it helped LOADS.
I would try counseling, and then if after that, take the pills. PPD, is a serious problem, though, and shouldn't be taken lightly.