According to their website,
http://www.teavana.com/c=faq/shop.axd/Static
only one tea contains gluten, Utopian Jewel Oolong.
Did you eat anything at the same time?
If not, you may want to call them and ask how they process their tea.
PS, FYI, I always Google the company and "gluten free" to find out if they have any info at all on their web...