I found St John's Wort didn't help with depression, and made me feel worse because of the side effects - tiredness, stomach upset, increased sensitivity to things I have an intolerance to. That may be why it's not recommended for those with a peanut allergy - it can make other intolerances worse. I have no idea how, but this happened with me.
I sympathise very much with wanting to find an alternative to antidepressants, and I'm glad for those who find St John's Wort helpful. I hope that anyone posting here who's trying it falls into that category, and it helps.
Please be aware, though, that it can have side effects, and can interact with other medicines or herbal remedies. So go carefully with it, and always check if you're taking anything else (even "natural" remedies) whether there might be an interaction. There's some good information here:
[DLMURL]http://www.mind.org.uk/help/medical_and_alternative_care/st_johns_wort_hypericum_perforatum[/DLMURL]
(although if you're taking anything else, I think you need to check with a practitioner about interactions, rather than just google it).