Unfortunately if you do not want to take medication or consent to seeing a therapist there isn't really anything that anyone can do for you. While I fully understand the aversion that may exists to being medicated, especially if you're sensitive to drugs or are leading a more natural and holistic lifestyle, I don't understand why you wouldn't wish to talk these thoughts and feelings over with someone who is trained at diagnosing issues such as PPD. You've taken the initial step in admitting that you feel as if there is a problem, rather than doing nothing about the problem, and running the risk that it may escalate my sincere suggestion is that you find a healthcare professional in your area who can assist you in some way.
I, too, would encourage you to explore your aversion to at least meeting with a counselor.
Short of that, do you have mama support in other ways? Mom' groups, a LLL meeting, or even just one other mom friend? That first year can be so exceptionally draining and exhausting, particularly when you are a new SAHM. IT IS HARD--at least it was for most everyone I know.
Be gentle with yourself. Try just one new thing and see if you feel better or worse: a mom's group, vitamins, eating a bit better, going for walks, etc.
Many, many women struggle with the same issues. It doesn't mean you are a good or bad mom, so don't lose hope. Try to reach out to somebody IRL, mama. Good luck.