I've had some experience with herbal suppliments. I've taken St. Johns Wort tea and didn't really notice anything. Maybe I didn't drink enough of it. Pills might be stronger.
I've also had Kava Kava tea and that made me sort of relaxed and sleepy. It's a good thing to take before bed. If you're really stressed and anxious, you might not feel anything.
I've also taken valerian root pills. These are surprisingly powerful and will totally relax you. The downside is that I felt groggy and it gave me a zombie-like look. Also, when I took it for a few days straight, I stated feeling depressed and I'm normally not a depressed person (just anxious).
Are you on meds? I just started prozac so I'm staying away from the herbal stuff because I hear they don't mix well together. If you give the St. Johns Wort a try, let us know how you feel. Take care!