Truvia is made from the stevia plant, however there are some small differences. Some people receive a reaction from one but not the other, so if you have problems with one of these, just try the other. Be sure to purchase Stevia as Stevia Extract Certified Organic as there are different types, and some forms actually contain Dextrose (sugar).
A little green tea should be alright. The only problem I have with any type of tea is that sometimes the tea will contain mold. Buying only organic teas should lessen the chance of this happening.