Hello!
Congratulations on your news. If you are anything like me you'll discover that even as your pregnancy progresses you still know less that you ever thought! Generally its a minefield of other peoples opinions!!!
As for the tea, I have googled it and found this:
http://www.babycentre.co.uk/pregnancy/nutrition/foodsafety/herbalteaexpert/ have a look at that link and see if that helps.
Good luck!
Tracey