Hi and welcome.

Just over a week is nowhere near enough time to assess whether or not something is working or not working. Your body is never the same compared to last time, simply because of aging. There are too many factors working in combination. Maybe log your food carefully and see what happens in a few weeks?

That said, based on my experience on St John's Wort, it wouldn't surprise me if it slowed one's metabolism. It seemed to make me seriously mellow. Seeing as my problem was the lack-of-energy form of depression, I stopped taking it.