Just for informational purposes, St. John's Wort doesn't really do anything for anxiety -- it's for depression, as well as other things (it's a nerve tonic and antiviral as well). And if you're on an antidepressant you shouldn't take it. You might try some ginger tea or ginger capsules and see if it helps the dizziness -- it can be very helpful for motion sickness and the like and symptoms like that.
It is possible that maybe you felt anxious about taking the St. John's wort. I know I get anxious starting new medications. And dizziness unfortunately it a very common symptoms of anxiety. If it worries you, there is not harm in seeing your GP to rule out anything else.
I took the St. John's wort one day two doses and forgot the next, and that next morning woke up dizzy. Haven't taken it since, and flew back and forth to Texas, and haven't felt totally straight since then. Although, I have taken Xanax in between and drank some. I just haven't ever been dizzy before. My Mother has and says its hireditary, and her brother also, I'm 33, and she said that's about when she started noticing veritigo type symptoms on and off. I'm just typical health anxiety sufferer, just thinking the worst. But, thank you for all of your responses, I'm glad to know I'm not alone. :)
This is one of the most common physiological components of anxiety, but that doesn't mean that's always the cause. But it often is, especially when combined with something like alcohol consumption. Did you stop the St. John's Wort, and if so, did that bring any improvement?