Sounds like it is not a very good quality stevia, even the tea like kind I had tasted good unless I put too much--then it had a bitter after taste. I bought the clear stevia from ebay seller csa1234. To make it easy to find his items he is selling I put the url to his items below. It takes a couple of weeks to get it though since he is shipping from Paraguay where the highest quality and sweetest stevia grows.
Another thing that might help your being diebetic is coconut oil, several people on the coconut-info yahoo group have weaned off of their diebetic medicine by taking four tablespoons of virgin oil daily. It is very expensive, about $60 a month for two people, but that might be cheaper than the diebetic supplies? Coconut oil is good for so many things, and is also anti-parisitical, anti-fungal. You can go to www.tropicaltraditions.com for a great deal of information, but Wilderness family naturals has better prices if you decide to buy. I'm trying to save up for a five gallon pail so I can save about $150. :) Hope that helps a bit...sorry your having such trouble. Caitlin Lorraine